When Rumours Come True: The Mew Trick

Back in the late 90s and early 2000s, an endless array of playground rumours circulated about Pokémon Red, Blue and Yellow, in real life and on the internet. A few of those strange rumours were real: in Red and Blue, going to the Safari Zone, Flying to Cinnabar Island and then Surfing on the coast really did cause Safari Zone Pokémon to appear; if you talked to the old man who teaches you how to catch Pokémon and then flew to Cinnabar and Surfed on the coast, you really would find a bizarre glitchy Pokémon called "Missingno." that was a Bird/Normal-type, knew Water Gun and Sky Attack (the former twice), and would give you 128 of the sixth item in your inventory when you encountered it.

The majority of these rumours, though, were made-up, just urban legends. Doing certain specific things in a certain specific order, they claimed, would unlock some sort of hidden secret that you couldn't access normally: amazingly powerful Pokémon known as "Pokégods"; a special item known as a Mist Stone that could evolve any Pokémon; access to Bill's secret garden, where you could catch all 151 Pokémon. The most famous of these rumours was the legend of Mew under the truck: if you went out of your way to skip the usual end of the S.S. Anne sequence,* Normally, the S.S. Anne will set sail and permanently block off the pier once you leave the ship after getting the Cut HM from the captain; if instead you either trade for a Pokémon with Cut or ensure that you lose a battle on the ship after getting the HM, the ship won't leave. then you could return later and Surf from the pier where the boat was to find a platform with a truck standing on it. If you then moved the truck with Strength, then supposedly Mew, the elusive star of the first Pokémon movie, would be under it. The platform with the truck was a real easter egg – but it couldn't be moved, and there was no Mew.

In fact, despite an array of different rumours on how to find it, Mew wasn't anywhere: it was a mirage of a Pokémon, one you could only legitimately obtain at in-person event distributions hosted only in certain places in the world for brief periods of time. By 2001, when I first found a website called Mew's Hangout, it had a page about how to obtain Mew, which patiently explained that no, there's absolutely no way to get Mew outside of the official events or using a cheating device. By then, this was settling in as the common wisdom among more world-weary fans: you can't find Mew in the game, we know this by now, and anyone saying otherwise is lying to you.

Slowly, over the next year or two, other rumours went the same way: there were no Pokégods, no Mist Stones, and the mark of a wise Pokémon fan was knowing not to believe these tales. Nonetheless, all those fake rumours were a persistent fixture on the internet, filling up websites' cheats sections for R/B/Y. While I'd believed and even tried a few of them when I was first devouring all I could find about the games on the internet, by 2002, when I was twelve, I'd wisened up and come to shake my head at all the nonsense.

I have this vivid memory of sometime back then, of stumbling upon some especially egregious, obviously fake cheat that ended with "I SWEAR THIS WORKS!!" As I scoffed and clicked away, I didn't memorize which site it was or exactly what the cheat was supposed to be, but the spark of frustration I felt in that moment stuck with me. Most sites had some retold or copy-pasted cheats that someone had simply read somewhere else and innocently believed – even Mew's Hangout had once bought into one of many rumours about how to find "Pikablu"* "Pikablu" was a hypothesized name for Marill, which had appeared in the "Pikachu's Vacation" short that aired before the first movie; at the time, only the first-generation games were out, so once people learned the movie had a Pokémon they'd never seen before, they dubbed it a 'Pokégod' and imagined there must be some secret way to find it in the existing games. In reality, of course, it was simply a teaser for the next games in the series, Gold and Silver – and Marill was neither related to Pikachu in any way nor at all rare or important. – but this felt like more of a straight-up lie, someone personally swearing to the truth of something that was clearly false. How far would people go to fool more gullible kids?

When I started this website in November 2002, I was staunchly determined that unlike those sorts of people, I would only tell the truth on it. Very early in its lifetime, no later than that December, I made a page called "Site Stuff I Hate" – a blunt, clumsy, very twelve-year-old list of common gripes I had with other websites I'd visited, in the hope it would spurn other webmasters to do better. One of the hates on the list was, "I hate sites with fake cheats, especially when they are said to work." I believe that one, and possibly the entire idea of making that page, was inspired by that particular memory. This stuff was all bunk, and people shouldn't be spreading it anymore – but they especially shouldn't be lying about it.

The Day Everything Changed

So, after all these years of fake cheats, of excited rumour mills finally fading into that jaded, cynical acceptance that it was all lies, on April 19th 2003, a user named TheScythe posted a thread on the GameFAQs message board entitled "Mew [Without GameShark or Nintendo Promotionals]". He knew he wouldn't be believed, already on the defensive in the first post:

From: TheScythe

If you don't believe me, try it yourself.
I predict about 99% of the replys to this post will be people who won't even try this, and will just poo-poo it the second they see it. If you bother even TRYING this code, you might actually see that this works. And, please, if your going to start and hate me, only hate me if the code didn't work for you. It should work. No mindless babbling about how I'm a liar. Because I'm not. About this anyway.

=========================================================

-Make sure you haven't battled the Youngster with a Level 17 Slowpoke, on the way to Bill's house. If you have, the code won't work.

-Also make sure you haven't battled the Gambler with two Poliwags and a Poliwhirl. He is facing the Underground Path toward Celadon city...on Route 8. If you have, the code won't work either.

-You need Fly. (Aka HM02)

-Get some Ultra Balls, and anything else you would use to catch a Level 7 Mew, that only knows Pound.

=========================================================

Go to the Gambler I talked about before. Save AT the door he is facing. Don't make him battle you. SAVE HERE, this is tricky. Now, step one step towards him, and PRESS START. Really fast. If you did it right, it will pop up, but he won't battle you. (This shouldn't work for any other trainer) Now Fly to Cerulean City.
[If you've done this right, after you use Fly, he will get the "!" over his head]

Note: You cannot use START, A, or B.

Note: Do NOT save anywhere after this. First of all, you can't save when your buttons don't work. But second, when they work again, saving will ruin the Mew code, and not allow you to get the Mew. Ever. Keep your saved file from before you battled the Gambler.

[If you've done this right, you can't press Start]
Walk (you can't use start) to the Youngster, and when you battle him, make sure he WALKS TO YOU. Don't go directly in front of him. Beat him, and (now your buttons work) Fly to Lavender Town (Or Saffron City).

[If you've done this right, the Start menu WILL pop up when it should]
Now if you went to Lavender, go to the left of town, and start to enter that narrow passageway. If you went to Saffron, go right, to where the guard lets you past if you give him a drink. Either way, the Start menu will pop up. Do NOT save here. Press B. Mew will appear. This is your ONLY chance. (unless you go to your save file before the Gambler) Ta-Da...its a Mew.

The first person to respond was open to it, but the next couple, just as TheScythe had predicted, adamantly shut it down:

From: RPGBrandon

This needs to stop NOW. You CAN NOT, I repeat CAN NOT, get Mew without either gameshark or going to a Nintendo promotional event. So let's just STOP with the rumurs already. (Especially unbelievable ones like this.)

From: Ratster

Indeed, I'm NOT going to try this code, but before you flame me, you should hear this:

The RAM coding of this game has been scoured countless times (I have also done this) in every area, and there is absolutely NO sign of Mew in the coding except for where all other Pokemon's names, stats, exp progressions, etc. are stored.

It didn't get traction until a particularly well-known and respected user, Jolt135 (who had written a major in-depth mechanics and strategy guide for the games), posted confirming that it worked – and even then it was met with confusion and disbelief:

From: Jolt135

What I wonder: Where do they pull 7 and 21 from if this indeed exploits timing glitches?

Oh, well. It doesn't matter. All that matters is...

IT WORKS!!!!!

From: gamefreak19

Are you sure jolt? or are you joking...

Somebody have too prove it false, by testing it...

... i should test it... it sound's like the most advanced glitch i heard...

From: David Kirk 7

I dont know if i would have believed this until Jolt said it was true.I need to go try this, who found out about this insanly complicated thing anyway?

After that, though, there was an explosion of confirmations. Jolt135 vouching for it got other users to give it a try, and one by one they came back to report it had actually worked for them too. From there, it spread like wildfire around the internet, and Pokémon fans around the world – me included – got to experience something that might as well have been a revelation that the Earth wasn't round. This was it: somehow, all along, there was a real, actual way to catch Mew in-game – and it looked just like the playground rumours.

Stranger than Fiction

Let's pause there for a moment, because it's illustrative to take a comparative look at an actual false rumour from back then, such as these instructions for how to catch Pikablu (as seen on the website PokegodLab):

1.First you must catch all 150 Pokémon NOT I repeat NOT using GameShark.

2. Then you also must have Seventeen of your Pokémon over Level 70.

3. Then when all of these tasks are complete, go to the guy in Pewter City who asks you if you have been to the Museum yet. Say NO so he takes you to the door.

4. Then go into the Museum and go upstairs and talk to the Lady who says "I want My boyfriend to catch me a Pikachu!"

5. After you talk to her, immediately come out of the door and once you come out of the door do not take any steps forward. left, or right. Immediately use fly and go to Celedon City.

6. Go into the Game Corner and talk to the Lady that says "Go Next Door to the Coin Exchange Corner to use your coins to get great Prizes!"

7. But this time she will say, "Hey? You have all the badges? WOW! Well then since you were nice enough to talk to me, I will give you this Pokemon I found stranded behind then Pokemon Museum, he is so strong I can not control him.But since you have all the badges, YOU TAKE HIM!

8. It will say, "You got ???????" Then when you try to use it it will just be like if you were pressing cancel and it will exit every time you click on it. Then go to Proffesor Oak and he will say the same thing he says when you give him Oaks Parcel, it will still say "YOU DELIVERED OAKS PARCEL!"

9. Then when you go into your pokemon line and it will replace the Pokemon in your first slot. So put a spearow or something in first. It will still be called ????? so go to the Nickname guy and change it to Pikablu. It has a ElectricWave, Psyshock, and Electrode... Dont ask me why its Electrode but its an awesome move.

10. It is a Level 999 and Pikablu will, Yes it will appear in your Pokedex! After 150 it will say 154 and then you look at the Pokedex Info and it will look like this...

Name: Pikablu Type: ??????? Height: 2" 3" Length: 3" 4"
Stats: Attack-999 Defense-999 Speed-999 Special-999
Attacks: ElectricWave,Psyshock,Electrode,SonicBoom. When you get 60,000 more experience points after catching it. It Learns SonicBoom when you gain around 60, 000 experience points and it kills any pokemon in one hit and it never misses!

There are several key similarities here, and in many other similar rumours, to the actual Mew trick. First, there is a high barrier to entry: your average player can't simply pick up their existing save right now, spend five minutes following the instructions, and say whether it worked or not. To verify this Pikablu rumour, for instance, you need to have completed your Pokédex without cheating, then train seventeen different Pokémon to at least level 70; most players won't meet these requirements, so they can't try it, and the rumour thrives in the space of that uncertainty. Likewise, the legend of Mew under the truck persisted because the vast majority of players had already missed their chance to try it – they'd exited the S.S. Anne the normal way, the ship had left, and after that they were forever unable to access the pier and the elusive truck. To test the trick, they would have to restart their game from the beginning, losing their original save – something most players were reluctant to do for a rumour. And then, well, they can't prove it doesn't work, right?

The authentic Mew trick's barrier to entry is strikingly similar to the truck legend: you had to refrain from battling two particular random trainers you'd had no reason to avoid, and if you had already battled either of them, like most players who'd already completed the game – too bad, you missed your chance, and to try it you would have to restart your save. It followed the exact transparent pattern of so many other rumours where, conveniently, it just so happens you're probably unable to verify it.

Secondly, a lot of these rumours tended to involve a strange, arbitrary sequence of seemingly random steps involving specific NPCs. For Pikablu, you supposedly had to talk to these two random people in Pewter, ones whose connection to 'Pikablu' was extremely opaque, and then suddenly a third NPC in a completely different city would give you Pikablu. The Mew trick, likewise, designates two seemingly completely arbitrary and unconnected trainers that you need to interact with in particular ways in order to unlock this secret Mew encounter, for some reason.

Thirdly, the steps tended to involve something oddly specific and finicky. You need to make sure you say NO to the guy who asks about the museum and let him take you there instead of walking there yourself; you need to come out of the door and immediately use Fly to go to Celadon without taking a single step. Implicitly, it's hard to stumble into it and easy to accidentally screw it up – which makes it sound more secret and exciting, and also means that if you tried it and it didn't work, then maybe you just didn't do it right, adding a veneer of plausible deniability. The Mew trick is likewise extremely finicky in this exact way: you need to stand in a particular spot, then press down and make sure you're quick enough to press Start, then immediately Fly to a specific place; you need to battle this other trainer, but you need to make sure he has to walk up to you first; you need to make sure you don't save in the middle of it or it won't work and your chance is gone forever.* Technically, nothing bad actually happens if you save during the trick per se, but the Mew encounter only happens if you battled the Youngster after your last reset, so if you save after battling the Youngster and then fail to catch Mew, resetting to try again won't actually get you another Mew encounter.

And fourthly, these rumours often involved some slightly glitchy-sounding behaviour, but only slightly – just enough to sound kind of weird and spooky and more exciting, but constrained by what a kid could comfortably think up without derailing their rumour-narrative. These would usually be things like being unable to do something, or getting some strange dialogue boxes, or something happening by itself. Pikablu is initially an item named ???????, and trying to use the item doesn't work, and talking to Professor Oak will make it say you delivered Oak's Parcel – a little spooky, but that's all. And the Mew trick is exactly like that, too: an exclamation mark pops up while you're flying away, your buttons stop working for a bit, your Start menu pops up by itself and Mew appears out of nowhere when you close it, but that's all. The most famous glitch in these games, Missingno., causes distorted and flipped graphics, permanently corrupts your Hall of Fame and duplicates your items, but the Mew trick isn't like that at all; the only visibly glitchy behaviour is subtle, innocent and temporary, exactly like the kind of weird semi-glitchy spice that kids sometimes added to their rumours.

Indeed, in TheScythe's GameFAQs thread, despite Jolt135's first post musing on whether it exploited timing glitches, by his next post he'd concluded that no way was this a glitch – it must have been intentionally programmed in by somebody at Game Freak as a secret specifically for unlocking Mew. Only then another user, gamefreak19, tried doing the same thing but battling another trainer instead of the Youngster – and had a level 7 Machoke pop out instead. It really was just a glitch – a perfect storm of game mechanics coincidentally coming together to create a striking imitation of the rumours.* Of course, it wasn't entirely a coincidence: the reason the playground rumours were the way they were was that they, in turn, were attempting in their limited way to imitate some of the actual glitches found in the games! The Missingno. trick also involved interacting with a specific NPC in a specific way before Surfing in one particular finicky spot in a completely different place, after all, and some of the slightly glitchy-sounding ones were obviously loosely inspired by some of the milder sorts of glitchy behaviour players had become familiar with.

Where Did It Come From?

TheScythe hadn't discovered this trick himself; he explained in the thread that he'd seen it on other websites, linking this page on GameTalk (as well as another link to the same site's Pokémon Yellow section, which was unfortunately never archived). That one is indeed another, more confusing telling of the same trick by a user named "Daniel26", posted a bit over a month earlier on March 9th 2003 – rated 1.6 stars out of five in GameTalk's tip rating system. Soon after the GameFAQs thread, White Cat of Azure Heights would snoop around and discover this even earlier source for the same trick on a site called JesseWorld, posted on May 31st 2002 by a user using the pseudonym "Nintendo" – where it had a single comment grumpily calling it bogus.* The commenter probably really did just do it wrong: if you don't press Start quickly enough, the Gambler will just challenge you normally, and the JesseWorld telling failed to emphasize the importance of the timing. The trick had clearly been slowly making its way around the internet, but for nearly a full year if not more, it had failed to make any waves.

When TheScythe made a FAQ on the Mew trick, he speculated that a rogue Game Freak employee had made it possible and then leaked it online:

Recently, a glitch to obtain Mew, was found. Many very low-traffic sites which are widely unknown had obtained this strange way to get Mew. How it was discovered? Nobody knows at the time, being as that it is such an obscure glitch.

My theory is that a worker at Game Freak, who has some part in creating or fixing this game, at tweaked it, so this strange glitch could be possible. Along with that theory, I think that worker, or someone who knew, put it on a random low-traffic site, after a few years, seeing how it would spread. Well, it spread all right. Right to GameFAQs, after I found it. [...]

Personally, I think it's just about impossible that the existence of the Mew trick was in any way intentional. The technical details make it very clear that it's not a built-in way to capture Mew specifically at all: it's a combination of a few different understandable programming oversights that ultimately cause a battle to be triggered based on incidental, unrelated non-encounter data lingering in memory from a previous fight. Following the instructions in this particular manner may innocently get us a Mew with no ill effects, but that's a fluke; in other cases, these oversights are liable to cause behaviour that is obviously strange, buggy, or even game-breaking. If anyone at Game Freak had discovered and realized the implications of these blunders while the game was in development, they would have had every incentive to fix them – it wouldn't have been a question of whether they wanted to allow a way to get Mew, but of whether they wanted to allow encounters created from garbage data. As a programmer myself, no programmer in their right mind would discover a bug like that and think, Let's keep this in here so players can stumble upon it; they would think, Oh, crap, that's not good.

A more plausible variant on the leak theory is that, while it wasn't intentionally left in, it was nonetheless originally discovered by an employee at Game Freak or Nintendo with access to the source code after the games were published, or else by some of the early fan researchers disassembling the game, such as the Japanese teamPA group, who were analyzing the games' mechanics and glitches in depth as early as 1999.* In fact, there exists a screenshot from teamPA's private message board where someone back in 1999 describes having run into a level 7 Mew after blacking out in Rock Tunnel and then returning – which we can in hindsight deduce was an instance of one variant of this glitch, though the original poster did not actually mention having blacked out during a random encounter that happened in front of a trainer, which would be the crucial element triggering it. I think Occam's razor suggests that means they simply didn't notice or realize the significance of that at the time, and if so, it's highly unlikely that teamPA actually got anywhere with understanding this glitch based on this incident – but that doesn't preclude them figuring it out later. That would mean the existence of the glitch was unintentional, but the Mew trick itself was put together very intentionally, by someone who had discovered the bugs in the code first and then worked out how to exploit them to get Mew before leaking the instructions to these low-traffic websites.* Generally, combinations of multiple minor bugs like this that together lead to something catastrophic are almost never discovered by programmers reading through the code, but someone could in theory have run into the trainer escape glitch by accident and then analyzed the code to learn more before working out how to catch Mew with it – after all, after TheScythe's thread, other researchers immediately began looking into what was behind this glitch and discovered a slew of other ways to make use of it.

I'm a bit skeptical of that explanation too, though, for a few reasons. The first is that the two surviving pre-TheScythe tellings of the trick (assuming I haven't missed any) both read like they were written up by children. They have a lot of clumsy grammatical mistakes; the instructions are brief and confusing and fail to properly emphasize the important bits (note the stark contrast to TheScythe's much clearer and more organized account); the JesseWorld poster is all-caps angry about people calling it bogus but even then fails to point to any specific thing they might have gotten wrong. These are all hallmarks of kids, who haven't quite fully developed the capacity to identify what might be confusing or opaque to others and express themselves accordingly. Maybe a lost one of these sites had an adult's explanation, and these other sites just had kids posting their own, clumsier retellings – but if there was a better, clearer, more credible-sounding explanation somewhere, why didn't that spread at all?

There is, of course, in theory a chance that an adult in the know specifically chose to post it 'roleplaying' as a kid, just as a social experiment in how long it'd take for people to catch on that this one was real if it was just as confusing as what the kids were posting, but at that point we're getting into more fanciful territory. And then there's also the question of why a presumably Japanese person would apparently choose to post it exclusively on English sites – as far as I understand it, the Mew trick only caught any attention in Japan after a post on the 2ch message board by user fifthヽ(´ー｀)ノ ◆Fi3PJTZKLQ, which appears to have been made on January 29th 2004, nine months after TheScythe's thread* Shoutout to this post by p4wn3r on the TASVideos forums for digging this up as well as the 1999 teamPA link, by the way; I disagree with some of the post's conclusions, but the timelines are gold, and while I'd already dug up the GameFAQs and Azure Heights threads and the JesseWorld and GameTalk pages from there, I had been having real trouble finding much of anything about when the 2ch post was made until I bumped into p4wn3r's writeup. – and of why, if they weren't a Game Freak employee or someone with a stake in keeping it quiet, they never published any of the analysis that must have been behind all this or stepped forward to talk about it after this hypothetical social experiment had succeeded.

More interestingly, though, you may have noticed that in TheScythe's telling of the trick, he suggests Flying to Lavender Town or Saffron City after battling the Youngster. On both the archived GameTalk page that he referenced and the oldest known surviving version of the trick on JesseWorld, however, there's no mention of Lavender Town – it just tells you to fly to Saffron and go out through the east exit. Flying to Lavender Town instead was either TheScythe's own innovation or possibly something that he got from a different, now-lost page where he'd seen it, though I suspect the former.* In particular, the GameTalk page that was archived was the first link that TheScythe provided in the thread; if a different page was the one whose version of the trick he relied on more, one would have thought he'd have linked that one first.

The Lavender Town route is plainly better: it's a much shorter path from there back onto Route 8. But clearly, looking at the history, the trick was originally discovered via Saffron, and then later TheScythe, or one of his sources, experimented and realized it would also work if you went through Lavender Town. Likewise, both of the earlier tellings we have start by telling you to go to Saffron City and go out through the east exit before stopping in front of the entrance to the underground; this is a completely unnecessary step, which TheScythe omitted, since what matters is just that you stand in that location in front of the Gambler. This implies something interesting, namely that the Mew trick as it first spread was not at all optimized.

That, I think, is pretty revealing. Any Game Freak employee or clever game mechanics researcher who actually understood how the trick worked and why would have known that the important part was simply that you Fly away from the Gambler, battle the Youngster and then return to Route 8 by whatever means – so why would it even occur to them to go back there via Saffron City, much less write it up as if you needed to go there specifically, not once but twice?

No, I think this initial lack of optimization suggests that the Mew trick was discovered by accident, probably by a child – someone who had no idea why or how it worked, only that Mew appeared if they followed these exact steps, and didn't really dare experiment with the method much. Once actual adults with the curiosity and know-how to start making educated guesses at the mechanics and trying different things got their hands on it, they immediately discovered the superior Lavender route.* The most convincing counterargument to this, to me, is that it would admittedly make a lot of sense for someone in the know to choose to use this particular Gambler to create accessible instructions for this glitch (it actually works with a lot of different trainers): he happens to be in a location where the exact spot you need to stand in at the start is easy to describe in words, right in front of the door to a house. But this is only vague, circumstantial evidence in favor of the discoverer potentially picking out the Gambler out of the possible set of trainers, which does not necessarily suggest a full understanding of the mechanics – and, of course, it's also entirely possible it just happened to be discovered via the Gambler by coincidence.

How It Might Have Happened

How does a kid discover something like this by accident? Well, there were literally millions of kids playing, after all; with numbers like that, I don't think it's quite so implausible.

It's inevitable that lots of those millions of kids playing the game would have accidentally triggered the trainer escape glitch at some point, simply by happening to decide they wanted to Fly somewhere else as they were walking, just when they obliviously happened to be walking into a trainer's line of sight. For this Gambler, it's very possible that originally, they were inside the building or the Underground Path itself and then figured they'd Fly somewhere, so they walked out and held the down button a little too long before they pressed Start.

Those kids who bumped into this would probably have been confused and alarmed to find suddenly they couldn't interact with NPCs or open the menu anymore; some would have just reset their game and then gone about their day. Others would have kept playing as best they could, from whatever location they'd flown to, then eventually managed to get challenged by a trainer they hadn't battled yet, and then the Start button worked normally after that. Probably many of them, once the Start button worked, would then have wanted to go back to see if that trainer who'd apparently spotted them before they flew away would still battle them (if you're trying to get back to the Gambler and not just to Route 8, of course you would Fly to Saffron, because that Gambler is near the Saffron side of the route), then had their Start menu pop up by itself; probably most of them, at that stage, would have been confused and pressed B. And some of them would have gotten a strange encounter with a regular Pokémon, or a glitch Pokémon, and just shrugged. But for a kid who happened to have avoided battling trainers a lot when they could, they also might have tried doing the same thing again, finding new trainers they hadn't battled yet each time to see what happened, since they couldn't rebattle the same one as before. And you only had to have one kid eventually happen to hit the jackpot with that Youngster and get Mew.

Once they'd hit that jackpot, of course, they would probably have tried to retrace their steps to tell their friends about it. They could physically show the actual Mew they'd caught, which might have been enough to persuade those friends to restart their game, even. Whether they'd found Mew on their first try or not, the exclamation mark when they flew away from the Gambler would serve as an obvious anchor when it came to trying to replicate it, the first thing in this little episode that had registered as weird, and provided a clear, sensible starting point for trying it again.* And if they'd entered from Saffron the first time they got Mew, they'd probably do that again just in case; having to go through Saffron's east exit twice has an interesting sort of symmetry to it that a kid with no idea what's really going on might latch onto as important somehow. And then, once they had managed to replicate it, once they were sure that these steps worked, they would have excitedly posted it online, in their clumsy way, or their friends would have posted it online...

...And then nobody believed them. Because why would anyone? It all just sounded exactly like all the other kids' urban legends about how to get Mew. Nobody believed anonymous kids posting it on sites full of made-up nonsense cheats; certainly they didn't believe it enough to painstakingly restart their save just to try it. The only people gullible enough to try it for a year would be other random kids – ones who were liable to mess up some of the convoluted, confusingly explained steps. And then, even if they did do it correctly and got their Mew, they would just become other anonymous kids posting it on other sites full of made-up nonsense.

How Does It Work?

In the weeks after TheScythe's GameFAQs thread was posted, the Pokémon fan community studied what was really going on here under a microscope. To my knowledge, the first widely publicized partial explanation of how the glitch works was published by White Cat here on May 7th, 2003, just a couple of weeks after TheScythe's thread was created; it also included instructions for how to use the same glitch to catch any desired Pokémon, which White Cat had quickly uncovered. However, there were still gaps to be filled at that stage – which they eventually would be over the course of the following years, thanks to the efforts of various fan researchers.* Unfortunately I don't know the full history of that research, and this article is already long enough, but for my own writeup here, I mainly referenced the Glitch City Wiki, the pret disassembly of the game code, some specific analysis by TheZZAZZGlitch, and some of my own digging and debugging.

Meta-Map Scripts

The Mew glitch happens because of what's called a meta-map script. Essentially, for a given map (location) in the game, the active meta-map script is some code that the game runs on every frame when you're in that location in the overworld and not in the middle of taking a step. Depending on the location, it might do different things, such as checking whether you've stepped onto a tile that should trigger some kind of cutscene. The index of the current meta-map script for each location is stored persistently in your save file, so that the game will know what should currently be going on on this map. For example, at the beginning of the game, Pallet Town will run a meta-map script that checks if you're exiting the town, and if so, it has Professor Oak show up to stop you and take you back to his lab (or, in Yellow, trigger the battle with Pikachu first); afterwards, the meta-map script index for Pallet Town will be changed to a different one that does let you leave town, so that the Oak cutscene won't happen again.

Normally, locations with trainers will use a meta-map script that we can call "Trainers Watching" by default. It's this script's job to check if you're within a trainer's line of sight; if so (and if you haven't defeated that trainer yet), it will (some irrelevant steps elided):

1. set a flag indicating you've been spotted by a trainer* This is bit 0 of address $CD60 in Yellow, or $CD61 in Red/Blue.
2. store some info on the trainer who spotted you in designated locations in memory* The ID of the trainer's trainer class – 217 for a Gambler – is stored at address $CD2D in Yellow, or $CD2E in Red/Blue, and the index of which Gambler out of the list of all Gambler trainers' parties – 5 for the Mew Trick Gambler – is stored in the next byte after that, $CD2E in Yellow or $CD2F in Red/Blue. $CF13 in Yellow or $CF14 in Red/Blue is used to store the index of which of the NPC sprites on this map represents this trainer – 2 for the Mew trick Gambler – which will later be used to retrieve their dialogue out of the list of all dialogues on this map.
3. set a different flag used to cancel the automatic downward movement on Cycling Road* This is bit 3 of address $D732 in Yellow or $D733 in Red and Blue.
4. display the exclamation mark bubble above the trainer's head
5. disable your movement inputs
6. if the trainer needs to walk up to you, set a flag indicating there's a scripted NPC movement happening, calculate how many steps the trainer needs to take, and initiate the NPC movement; this will cause them to walk that many steps and then clear the NPC movement flag when they're done* The scripted NPC movement flag is bit 0 of address $D72F in Yellow or $D730 in Red and Blue.
7. change the meta-map script index for the location to point to a different script, which we can call "Start Trainer Battle"

The "Start Trainer Battle" map script used after a trainer encounter is initiated is simpler. First, if the trainer is still walking towards you (as indicated by the "is scripted NPC movement happening" flag), it will do nothing and wait until that flag has been cleared. Once that flag is cleared, it will display the trainer's pre-battle dialogue and then (once you have gone through and dismissed the dialogue box) initiate a battle, based on the info that the "Trainers Watching" script stored about the trainer.

Where the Game Gets Confused

Most of the time, when you step into a trainer's line of sight, the "Trainers Watching" map script means they will immediately notice you and walk up. However, certain trainers, like the Mew trick's Gambler, have a particularly long line of sight, so that they can notice you the moment they come onscreen. The trouble is that the "Trainers Watching" script will ignore any offscreen trainers, so as not to waste time on them, and for a split second after you've stepped into what is technically the trainer's line of sight, their sprite is still marked as being offscreen, because that data has yet to be updated. Thus, effectively, for that split second, the trainer can't see you yet.

This means that if you're facing them head-on, you can take an extra step towards them before they spot you if you just hold down the directional button, compared to if you'd stopped after a single step (try it!). But more importantly, it also means that if you press Start in time, the menu will open before the map script actually realizes you're within their line of sight. This allows you to choose to Fly away (or use another menu-based method of escape – Dig, Teleport or an Escape Rope), even though you're now within range of the trainer. This is programming oversight #1 – a very innocuous one that by itself wouldn't matter at all.

As you're preparing to escape the route, though, the current map script gets executed one more time, because the game does that before it checks if you're about to warp somewhere. Since it's the "Trainers Watching" script, and you're within the trainer's range, it sets those flags, stores the trainer's data, displays the exclamation mark and initiates the NPC movement, and then it faithfully sets the meta-map script for this location to the "Start Trainer Battle" script – even though you're about to leave this location altogether. This is programming oversight #2: you are not meant to ever leave a location after switching to the "Start Trainer Battle" script. Disabling your movement inputs, the "spotted by a trainer" flag which prevents you from opening your Start menu, and even the flag that disables the auto-movement on Cycling Road were meant to prevent you from moving in any fashion after being spotted by a trainer – but because of programming oversight #1, it is possible for the player to press Start first and then get spotted afterwards as they're leaving the map.* To fix this, the "Trainers Watching" script should check if you're about to warp somewhere else and skip letting trainers spot you if so, and/or ideally leaving a location should always explicitly reset these flags and the meta-map script back to normal just in case. Without both of these oversights, this glitch would not be possible.

Once you've arrived at your destination, the game will re-enable your movement inputs, but the "spotted by a trainer" flag and the scripted NPC movement flag are still set. This leaves you able to move, but unable to open the menu or talk to NPCs, because the "spotted by a trainer" flag disables that functionality (after all, the game doesn't want you to open the menu or start a dialogue with a different NPC while a trainer is walking up to you). And, crucially, the meta-map script for the map where you flew away is still set to the "Start Trainer Battle" script.

If you then walk into a different location with trainers, you can still get noticed by a different trainer there – after all, changing the meta-map script for one route doesn't change anything for any other route, which will still be running the "Trainers Watching" script as normal. So, provided you make a trainer there, such as the Route 25 Youngster, walk up to you, the scripted NPC movement flag will be reset when they're done, and the trainer encounter flag will be reset when you've finished the battle, bringing the game state mostly back to normal again.* If the trainer doesn't need to walk up to you, on the other hand, the game will freeze, since the "Start Trainer Battle" script will just wait forever for the lingering NPC movement flag to be cleared – the game doesn't expect that flag to be set at this point if the trainer wasn't about to walk anywhere. The only oddity that remains is that on the original map with the long-range trainer, the meta-map script is still set to the "Start Trainer Battle" script.

Returning to the Original Map

So, when we return to the original map – Route 8 in the original Mew trick – the "Start Trainer Battle" script will faithfully do its thing: check that the NPC movement flag has been cleared (which it has), then display a pre-battle text box and initiate a battle.

Only, by now, the locations in memory where we stored the info on which trainer we're supposed to be battling no longer contain the data for that Gambler on Route 8, or whichever long-range trainer triggered the glitch. First, they all got overwritten with the Youngster's data when the Youngster noticed us, or whichever trainer. And then... the thing is that the game has a limited amount of memory, so data that it expects to only need temporarily may be cheerfully overwritten with other data for other purposes later. This information on the battle that's about to start is normally extremely temporary: we only need to keep it around from when the trainer spots us in the overworld until they've walked up and we can start the battle. So, during the battle with the second trainer, this data got overwritten again: while in battle, the memory locations that we just used to store the trainer class and which team of Pokémon we were about to face are instead used to store the enemy Pokémon's out-of-battle Special stat and its Attack stat stage.* Technically, it's just the low byte of the enemy Pokémon's Special – effectively, if the enemy has a Special greater than 255, then this memory location will contain the Special mod 256, or the remainder if you divided it by 256. And when we open the Start menu to fly back, that actually overwrites which text box will be displayed... with the Start menu itself!* Specifically, whenever we display a text box, it's based on an index that normally indicates which sprite on the map we're interacting with and thus which of the map's dialogue texts we want to show. The Start menu is actually considered dialogue for this purpose, always represented by index 0 since it's accessible everywhere. Talking to an NPC, reading a sign, etc. before reentering the original map will set that index again and result in attempting to initiate a corresponding piece of dialogue from the map instead of the Start menu, which may then have other, glitchier side-effects if that is for instance an actual trainer's pre-battle dialogue. When performing the glitch, always make sure the Start menu is the last text box you looked at unless you're sure you know what you're doing.

All in all, this means that once we enter the route, the meta-map script activates, verifies the NPC movement flag is clear, displays the Start menu where it thinks it's displaying a trainer's pre-battle dialogue, and then once that text box is closed, it starts a battle – not with the trainer we were supposed to be battling, but with whatever corresponds to the Special stat and Attack stat stage of the last Pokémon we battled. The fact this can happen is pretty bad – this data is not meant to represent a battle and could be virtually anything! So, while this situation ever coming up is still just downstream of the combination of programming oversights #1 and #2, I'm going to call the fact we're blindly creating an encounter out of this data here programming oversight #3.

When we're performing the Mew trick as instructed, though, it all works out beautifully. The Youngster's only Pokémon is a Slowpoke, whose Special stat is always 21 – the internal index number for Mew.* In the first-generation games, the internal index number order is completely different from the Pokédex order of the Pokémon; the list starts with Rhydon and Kangaskhan and is likely a rough reflection of the order in which the Pokémon were created during development, though Mew likely replaced a Pokémon that had previously been removed. And the Slowpoke's Attack stat stage... well, by default it's 7, because a neutral stat stage of 0 is internally represented as 7. If you use a move like Growl while fighting the Youngster's Slowpoke, you can lower its Attack stage all the way down to the minimum of -6, represented as 1 – but if you don't do that, it's going to be 7.* The fact you can manipulate Mew's level to be 1 actually enables even more shenanigans.

And as it happens, the first-generation games don't really differentiate between trainer and wild Pokémon battles when it comes to initiating them. The index numbers up through 190 simply represent Pokémon,* There are 39 dummied-out "Missingno." entries here and there in the sequence, likely once Pokémon that were later scrapped. while index numbers 201-247 represent trainer classes. (This is why some glitches will let you encounter a trainer as if they were a wild Pokémon.) If the index number represents a trainer class, then the second number will be used to choose which Pokémon team they should have; if it represents a Pokémon, the second number is instead used as the level of the Pokémon encounter. Hence, the "Start Trainer Battle" script that was meant to start a battle with the Gambler blissfully starts a battle with a level 7 Mew instead, as if nothing were more natural.

The Aftermath

Once we've fought Mew, the game seems pretty much back to normal. Because we completed the battle, the map script returns to the normal default "Trainers Watching" script. Everything is simply back to the way it's meant to be, with no lingering evidence that you did anything strange, other than your new Mew. Right?

Well, normally, when a wild Pokémon battle is triggered through the "Start Trainer Battle" script, that's because it's a stationary encounter, like a legendary Pokémon (which, as far as the overworld is concerned, are the same thing as trainers!). And when we win a battle against a stationary wild Pokémon, there's one more thing the game does: it removes the Pokémon from the map.

Each map has its own set of overworld objects that can be added to or removed from the map over the course of the game, with the status of each persisted in your save file. These include items (which disappear when you pick them up), NPCs that appear or disappear when certain story events happen, as well as the stationary overworld Pokémon, which disappear after you've beaten or captured them. When you win a wild battle triggered through this glitch, the game assumes it was a stationary encounter, and the game will attempt to flag the object you just interacted with as gone from the map.

But after performing the glitch, the memory location where it would have stored which object that was is set to 0, which will not match any actual removable object on the map.* Specifically, it's set to the same index that determined which text box to show; if you talked to an NPC or read a sign, etc., it will be different, and in fact it might match the index for an actual removable object on this route, in which case that will indeed be the one removed. Instead, the game will go through the list of removable objects for this map, try to find it in the list, fail to, and then... because there is no error checking for the case where the object index is not found in the list, it just tries to remove whichever object is indicated by the memory location that comes directly after the end of the removable objects list. For technical reasons, this will generally be the remnants of the lists of removable objects for previous locations you were in. This is programming oversight #4: the game will try to flag some arbitrary, unrelated object as gone from the overworld after the battle. As these programming oversights go, this one is easily the least excusable – though once again, it's something that wouldn't be a problem without the other oversights making these unexpected situations possible.

So, if you performed the Mew trick via Lavender according to TheScythe's instructions, you will Fly away from the Gambler on Route 8, which has no removable objects. Then you will go to Cerulean City, which has several; then you'll walk through Route 24, which has two; then you'll enter Route 25 to battle the Youngster, which has one; then you'll Fly to Lavender Town, which has none; and then you'll step back onto Route 8, which has none. Because the Route 8 list is empty, it will instead try to remove the first removable object from the last location you were in that did have removable objects – namely, Route 25's Seismic Toss TM.* Specifically, each subsequent list of removable objects essentially gets pasted on top of whatever list was already there, so that if it has at least one removable object, the first one replaces the first slot, if it has a second one it replaces the second slot, and so on – when you go from Cerulean to Route 24, the first two items on Cerulean's list will be replaced with Route 24's two items, and then when you go from there to Route 25, just the first slot gets replaced again with the Seismic Toss TM, without touching the rest. Going to Lavender or Route 8, with no removable items, will then just leave the list as is.

Now, by the time you could perform the Mew trick this way, you'll have already progressed far beyond Route 25 – you've likely already picked up the Seismic Toss TM, even if you intentionally skipped battling this one Youngster. So no harm, no foul – the game just sets a TM to be gone that was already gone anyway. If you had performed the Mew trick via the alternative Saffron City route, though – flying there after battling the Youngster and then heading east to Route 8 – then you'd have visited Saffron City just before Route 8, and the trick would have removed the first removable object there: the Rocket who blocks Copycat's house until you clear out Silph Co., which you may or may not have done yet. Though that one is very insignificant – even if you haven't chased the Rockets out of Saffron yet, it just gives you slightly early access to Copycat and the Mimic TM, and once you clear Silph Co., all those Rockets are supposed to disappear anyway – in general, depending on where you go when you perform the glitch, different objects or NPCs can end up getting permanently removed from the map. The possibly most popular way to perform the Mew trick today, where you use the long-range trainer lurking in the grass on the left side of Route 24 rather than the Route 8 Gambler, results in the disappearance of the police officer outside the ransacked home in Cerulean, which has no gameplay impact but does forever mark your save file as one that has performed the glitch.

With TheScythe's Route 8 Gambler and Lavender Town method, correctly performed, though, there truly is no downside, so long as you already picked up Seismic Toss. You have your Mew, and other than that, your save file is perfectly normal. And considering the degree of shenanigans involved behind the scenes – spending a while in a game state that was never meant to be possible, generating an encounter based on arbitrary junk data, blind removal of an arbitrary overworld object – that fact is nothing short of miraculous. The Mew trick is truly the most beautiful video game glitch I've ever seen: the holy grail of Red, Blue and Yellow, achieved through just a few magical steps that barely sound like a glitch at all, with no lingering ill effects so long as you do it right. And that's pretty amazing.

Epilogue

As time passed after the Mew trick was first publicized, something slowly began to nag at me. Something about it, I realized, might have sounded vaguely familiar. And my mind kept drifting back to that one website, the one with the obviously fake cheat, the one that insisted, "I SWEAR THIS WORKS!!"

Had my twelve-year-old self unwittingly, in her arrogance, made a disgruntled page about hating fake cheats on websites after seeing and dismissing the real, honest-to-god actual Mew trick? After all, I made that page in late 2002 – well after when we now know the trick was already quietly circulating.

I never could know that for sure; after all, I'd just immediately dismissed it and left, without memorizing any details. But I wrote a little musing about it here on the site at the beginning of 2005, and after that I always had that thought in the back of my head – that I might actually have seen the Mew trick in the wild in 2002, before TheScythe's discovery. And in January 2024, when I first bumped into the archived JesseWorld page from a Bulbapedia citation, my first reaction was oh my god, this is it. There it was: the Mew trick, in 2002 just like I thought, ending in defensive allcaps insistence that it totally works. This must have been the site that I saw, and it really was the Mew trick.

In truth, after mulling it over, I think it probably wasn't literally it. If you'd asked me to describe the color scheme of that site, off my vague memory, I would've said black and purple, and the memory I thought I had of the phrasing of that allcaps bit was specifically "I SWEAR THIS WORKS!!" I could definitely have just been remembering a paraphrase I came up with when I added a specific reference to it to the "Site Stuff I Hate" page, or mixed up the color scheme with another site I visited back then, but when both are off from what I think I remember, probably it wasn't that exact site.

But the Mew trick had been circulating on more sites than that, ones that have now been lost to time. On an archived version of the submission list for the games on JesseWorld, where the Mew trick submission can be seen at the bottom, we can also see someone responding to the Mew trick's submitter:* I deeply wish the two responses to this post had been archived, but alas, it seems that although that page was crawled twice, both times it just redirected to a "Too Busy" page.

to a kid named nintendo
ok listen up kid, stop tring to pull off this mew gig we all know your posting it every where so you can be a top coder so knock it off while four people belive. it is impossible to get mew without the gamshark or trading so just stop it
-- From souwant2be on 6/25/2002

This suggests that, at least by late June 2002, the Mew trick had already been posted not just on JesseWorld but on many different sites, whether by "Nintendo" themselves or by those scant few other kids who'd actually tried it – and already others were just assuming it was fake and getting sick of seeing it. Surely one of those sites could have had a black and purple color scheme. And why wouldn't one of these desperate kids posting it elsewhere, who'd tried it, who knew it worked but kept getting brushed off, have attached the words "I SWEAR THIS WORKS!!"?

The thing that ultimately sticks with me, beyond that vague nagging ghost of familiarity, is that I remember finding that cheat especially obviously fake, and that's definitely what the Mew trick would have seemed like to me at the time. After all, it was a cheat relying on precise button timing, in a game where nothing at all is about button timing and reflexes. Wasn't that absurd? Wasn't it ridiculous to propose that, even if you could somehow press Start so quickly the menu pops up before the trainer sees you, they would somehow still see you anyway while you're flying away? I knew nothing about the actual programming of Game Boy games at the time, but in my naïve mental model of how I assumed the game worked, this seemed a straightforwardly silly proposition – obviously the game wouldn't activate things like trainers spotting you during a static animation. I distinctly remember this line of reasoning, remember thinking this at some point; I don't know if it was at that website, or even after TheScythe's thread, but it's a thought process I remember having.

So... I can't know if it was the Mew trick that I saw there, but perhaps the more salient point is that it might as well have been. I never would have taken this trick seriously for a moment if I'd first seen it from some random kid on a website defensively insisting it works in allcaps, instead of after a bunch of serious, knowledgeable grown-ups with solid reputations had confirmed it and posted screenshots. I used to wonder if seeing it back then meant it could have been me who catapulted the Mew trick into prominence – but it never truly could have been me, because the Mew trick was just such an incredibly fake-looking glitch, and I'd been burned by far too many fake rumours that had made me a cynic.

I find it truly tantalizing to think about this time, though: about these kids who had tried a trick to get Mew that really worked, before anyone else, but had no way of proving it and sounded exactly like all the other ones making up stories; about all the other kids, like me, who dismissed them out of hand, because of course it was fake. If not for TheScythe giving those kids a chance, and Jolt135 giving him a chance, we all might have gone on much, much longer blissfully unaware that this beautiful, beautiful, one-in-a-million glitch was real, beaten out by the more open-minded kids who just saw it and tried. And I think that's pretty fascinating.

Page last modified March 11 2025 at 23:41 UTC

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