Welcome to Vol. 3, issue 50 of Johto Times! This week we have a very interesting write-up by Dragonfree about a glitched Jolteon from her beloved copy of Pokémon Yellow, and how she was able to solve the mystery of how and why it happened twenty years later!

Now that we are in December, the Johto Times team are taking a well deserved rest. For this reason, we will not be updating our news, and our mailbag will not be monitored during this time. A recap of the noteworthy headlines will be available in our January newsletter! Any important news announcements will be made on our Bluesky account and on our Discord server. You are welcome to join us on the Johto Times forum too!

Feature: The Curious Case of Dragonfree's Glitched Jolteon

Dragonfree:

On my old Pokémon Yellow Version save file – the one I loved, the one I started shortly after beating the game for the first time when I was ten years old because I didn't know you could just continue after beating the Champion – I had a glitched Jolteon.

Specifically, when you tried to view his stats, the screen would just go blank. It really freaked me out the first time it happened; I thought the game had crashed somehow. But when I pressed A after that, the stats did appear – only some of what was meant to be on the status screen was missing. (In particular I remember vividly that the IDNo/ and OT/ labels were missing.) The second status page was perfectly normal. This happened consistently, exactly like this, every time I viewed this one Pokémon's stats. There was nothing wrong with any other Pokémon I had, or anything else in the game, and in every other respect he was just a normal Jolteon. But he was glitched, so he was different, so he was awesome.

Jolteon hadn't been one of my original team members on that save file. But after beating the Champion (by this time I knew I could continue afterwards), I had set about training up other Pokémon off my PC, both to complete my Pokédex and just for fun, and one day I took out my Eevee, the one I'd gotten from Celadon Mansion during my playthrough. I'm pretty sure I discovered the glitch the first time I viewed his stats after withdrawing him. I remember being torn about evolving him; I had the thought that maybe evolving him would fix him, reset whatever was going on, and while on the one hand I didn't want this weird glitch to mess up my game somehow, on the other hand this was something weird and unique and kind of cool. But as luck would have it, he stayed exactly as glitched after I’d used the Thunderstone. If not for the glitch, I would probably have just put him back on the PC after training him up to catch up with my team at the time, like all the other Pokémon around that time that I trained to high levels just because I felt like it. But as it was, Jolteon was special, so I just had to keep him on, even though having a second Electric-type alongside my Pikachu was kind of redundant. He became a permanent team member, and I showed him off to anyone who would care (mostly my cousins).

Artwork of Jolteon, created by Dragonfree

Dragonfree:

I never knew why my Jolteon was glitched. It was a genuine cartridge, bought new, and I'd never used a cheating device or exploited glitches of any kind. (One time, I'd attempted to perform the classic Old Man Missingno. trick after reading about it online – but of course it hadn't worked, much to my disappointment, because I was playing Yellow, which had fixed that particular glitch.) At the time, I only had the vaguest idea of a "glitch" as being when something just randomly happened wrong on the game; I didn't question what was actually going on here that was making this consistently happen for this one Jolteon, and I didn't have the knowledge or mental capacity to properly assess exactly how weird it was. For all I knew, maybe this just happened sometimes.

In 2003, when I was thirteen, I let a cousin visiting from Denmark play my Yellow version for a bit, and she started a new game and saved. (It wasn't really her fault – she had little reason to know that an innocuous-looking menu option in an unfamiliar game would just delete my own progress with little warning, and I sort of realized that but didn't know how to communicate that to her with my limited Danish.) I was absolutely devastated – for all the hundreds upon hundreds of hours I'd sunk into it, completing my Pokédex and training up so many Pokémon, but mostly because I was very emotionally attached to my team: the Pikachu that I'd trained to level 100 (I'd done it in a frantic, desperate bid to make him happy again after I'd deposited him on the PC once to try a dumb rumour about how you could get into Bill's secret garden if you had six specific Pokémon in your party), the Charizard that had made me love Charizard, Blastoise, Pidgeot, Dragonite – and, of course, my glitched Jolteon. When it happened, I'd been in the process of training up the rest of the team to level 100 through repeated rounds through the Elite Four, but they never made it there. In the intense way that only kids can feel, it was like losing friends.

After a while, I started a new file and tried my best to recreate my old save: I named myself TRAINER (something I'd done when I was ten because it felt more official, somehow), I caught the same Pokémon, I put together the same team as before. I got Eevee from the Celadon Mansion with bated breath: maybe some sort of production error on my cartridge meant that the Celadon Eevee would always have the same glitch? But no: my new Eevee was just a normal Eevee. In a very definitive, tangible way, it would never be the same.

Back then, I mainly just grieved my lost partner. The glitch only mattered because it had made him special. But years later, by the time I had a degree in computer science and had personally dug into some of the games' programming, my thoughts began to wander back to my Jolteon. Glitches in video games aren't just something being weird at random by magic: there had to be a concrete explanation for what was happening there. And yet, in all those years since, as fans discovered and documented everything from exactly why Missingno. has the stats it does to ways to completely break the game and make it blissfully execute arbitrary code, I had never, ever seen another person describe the same glitch that had happened with my Jolteon or anything like it. I knew it was real – it wasn't something that'd happened once that I could have been dreaming or imagining, but something that had happened consistently, every time – but now I didn't have that save anymore to verify it, or even so much as a video of it (video recording devices weren't anywhere near as ubiquitous back in the early 2000s as they are today).

I burned with curiosity: what was actually wrong with my Jolteon? Why would it cause these weirdly specific effects? I made a post about it on my Tumblr in 2015, and at some point I went and dug through the pret disassembly of the Pokémon status screen code (effectively a cleanup of the game code that's on the official cartridge, made to be a bit more human-readable like the original source code would have been), just to see if anything stuck out to me that might explain it. But nothing really did, and I ended up giving up on that line of inquiry and moving on to other things.

Eventually, in early 2024, I happened to go on a big nostalgia binge about the first-generation games and their glitches, and once again I thought of Jolteon, this time from a slightly different angle. Since the glitch happened consistently to Jolteon and only Jolteon, there had to be something unusual in Jolteon's data structure. And how could something have happened to my Jolteon that seemingly had never happened to anyone else's Pokémon, as far as I'd heard anywhere on the internet, in the twenty-plus years since? It probably wasn't some kind of thing I'd inadvertently done in-game to cause it – I'd never toyed around with memory corruption or anything of the like, and if it had just been something I'd done by accident during normal gameplay, surely other people would have bumped into and described this issue over the years. Instead, my thoughts began to drift to a rare kind of glitch, where a cell in a memory chip erroneously flips from 0 to 1 or vice versa due to one-off hardware interactions, such as from charged particles set off by cosmic rays. What if what had happened to my Jolteon was unique because it really was caused by a one in a million sort of event – something like a charged particle that happened to hit the bit of memory storing the Pokémon on my PC in just the right place?

This was just speculation, but it gave me a theoretical place to start thinking about the problem again. I quickly managed to narrow down that whatever was odd about Jolteon must have been part of one of the two fields in the Pokémon data that stored text: the nickname and original trainer name. And after looking up how the games encode text data, I could taste the answer: it had some special characters, known as ‘paragraph’ and ‘page’, used to denote when a new ‘page’ of dialogue or Pokédex data began, which instructed the game to wait until the player presses a button before continuing.

I had already backed up my ‘new’ Yellow save, the one I’d started after my cousin restarted it, using a backup device. I loaded it up in an emulator, located my normal, non-glitched Jolteon's data in the game’s memory, and overwrote the ‘end string’ character at the end of his OT name with the ‘page’ character. I opened the menu and went to Jolteon's stats. And lo and behold, there was the familiar blank screen! I pressed A and...

Jolteon's status screen with a 'page' character in the OT name

Dragonfree:

Okay, okay, this wasn't quite what I thought I remembered. I was pretty sure the type had shown up. But the missing labels were definitely correct, exactly like I remembered it. The ID number being there even though the label wasn't was correct. Something like this was definitely it. A single modified character in the OT name really could cause both an initial blank screen and subsequent missing labels on the first status screen.

Moreover, when I subsequently tried overwriting the ‘end string’ character with the ‘paragraph’ character, that resulted in something even closer to my memory of my Jolteon:

Jolteon's status screen with a 'paragraph' character in the OT name

Dragonfree:

And – the ‘end string’ and ‘paragraph’ characters were exactly one bit apart. A one-in-a-million occurrence flipping just one single particular bit in the game’s memory from zero to one could have made that change.

In other words, my Jolteon, back in 2001-2003, was glitched because he had a special character in his OT name – possibly caused by an errant cosmic ray whose byproducts just so happened to hit an Eevee's PC data in a way that simply made him very special, with no other ill effects.

It was still somewhat mysterious to me why the labels and OT name were missing from the second status screen – but with this context, about precisely what had been off with Jolteon’s data, I was then able to look at the status screen disassembly again and figure out exactly what was going on there.

It turns out that when the game encounters the ‘paragraph’ character, which is only meant to be used within in-game dialogue to denote the start of a new ‘paragraph’ of text, it will wait for a button press and then clear out the area of the screen corresponding to the contents of the dialogue text box so that it can then write the next chunk of dialogue there. The ‘page’ character, which denotes the start of the next page of a Pokédex entry, similarly clears out the area of the screen corresponding to where the Pokédex entry is written in the Pokédex:

Two screenshots showing, highlighted in red, the areas of the screen cleared out by the 'paragraph' (left) and 'page' (right) characters - corresponding to the dialogue textbox and Pokédex entry text, respectively

Dragonfree:

Meanwhile, when the game renders a Pokémon’s status screen, it does it in a bit of a strange order, preparing the different elements of the screen before making them visible all at once. By the time it tries to write out the OT name, it has already written out the TYPE1/, TYPE2/, IDNo/ and OT/ labels that go on the right side of the screen as well as the Pokémon’s type, but not the box containing the Pokémon’s stats on the left side or the ID number itself. As we’re writing out the OT name, because of the glitched character at the end, we stop to wait for the button press before we’ve actually made any of these elements visible – hence the completely blank screen. And then, once we’ve pressed the button, we clear out everything from the area corresponding to the dialogue box. This is how those areas line up on the status screen, for the ‘paragraph’ and ‘page’ characters:

Two screenshots showing how the cleared-out areas for the 'paragraph' (left) and 'page' (right) characters line up on a Pikachu's status screen

Dragonfree:

So, if we encounter the ‘paragraph’ character at the end of the OT name, we'll blank out the area in the left screenshot. This will erase the IDNo/ and OT/ labels that we already placed, as well as the OT name itself. However, we don't draw the ID number or the stats box until afterwards, so those will still show up fine!

Meanwhile, if we encounter the ‘page’ character in the OT name, we'll blank out an even bigger portion of the screen, now wiping out the type as well, though the TYPE1/ label is spared since it's just outside the affected area. Again, though, the ID number and the stats box are drawn afterwards, so they're still shown as normal.

My original glitched Jolteon was a dear, special teammate now lost forever to time – but two decades later, I have finally worked out what was going on with his strange status screen and how it probably happened, and there's a big sense of catharsis in that. I haven't made the artificial bit flip permanent for my new Jolteon, but I hypothetically could do that and then write the save back to the cartridge, where I could watch it happen on my Game Boy Color for the first time in twenty years. I don't think I will, at this point – it still would never be quite the same. But solving Jolteon's mystery feels like an appropriate way to honor his memory.

Goodbye, Jolteon. You were very, very special.

Artwork of Jolteon, by Dragonfree

We appreciate Dragonfree for sharing such a great memory of her very unique Jolteon. It's incredible that you were able to discover how this glitch occurred all of these years later, and what made it so special! Thank you for sharing such an in-depth explanation, and for your amazing Jolteon artwork!