You’re surfing along the coast of Cinnabar Island. The music is repetitive, almost hypnotic. Suddenly, the screen stutters. The battle transition swirls, but the sprite that appears isn't a Tentacool or a Magikarp. It’s a jagged, backward-L-shaped mass of static and scrambled pixels. MissingNo. has arrived.
If you played Pokémon Red or Blue in the late 90s, this wasn't just a bug. It was a rite of passage. It was the "King of Gaming Bugs." Most glitches break a game and make it unplayable. MissingNo. did something different. It broke the game in a way that felt like uncovering a forbidden secret, a digital ghost lurking in the code of your Game Boy cartridge. Even now, decades later, developers and speedrunners study it. It isn't just a mistake; it’s a masterclass in how hardware limitations create unexpected behavior.
What Actually Is MissingNo.?
Let’s get one thing straight: MissingNo. isn't a Pokémon. It isn't a "deleted" monster or a "secret" Mew evolution, despite what the playground rumors told you in 1998. The name literally stands for Missing Number.
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To understand why it exists, you have to think about how tiny a Game Boy cartridge is. Space was at a premium. Nintendo’s developers at Game Freak used every byte like it was gold. In the game’s code, there are 256 available slots for data related to Pokémon species. However, the first generation only had 151 monsters. This left 105 empty slots. Instead of leaving them blank, which could cause the game to crash if accessed, the developers filled them with placeholder data.
When you trigger the glitch, you’re forcing the game to look at one of these "empty" slots. The game tries to render a Pokémon that doesn't exist. It pulls random data from the game’s memory—including the player's name—and tries to turn it into an image. That iconic blocky sprite? That’s just the game’s "sprite-drawing" engine hallucinating.
The Old Man and the Sea (of Glitches)
Most people remember the "Old Man Glitch." You talk to the guy in Viridian City who shows you how to catch a Pokémon. For some reason, during that tutorial, the game swaps your player name with the word "OLD MAN." To keep your actual name safe, it temporarily stores your character’s name data in the same memory location used to determine which wild Pokémon appear on the next map you visit.
Usually, this isn't a problem. You walk into tall grass, the game overwrites that temporary data with "Pidgey" or "Rattata," and life goes on.
But Cinnabar Island is weird.
The narrow strip of water on the right edge of Cinnabar Island is technically a "wild Pokémon" zone, but the developers forgot to program which specific Pokémon live there. So, the game doesn't overwrite the memory. It looks at the data where your name is stored and tries to translate those letters into Pokémon ID numbers. If your name is "DAVE" or "ASH," the game might look at the characters in those names and say, "Okay, the third letter is 'S', which corresponds to ID number 000. That’s a MissingNo."
It’s a perfect storm of programming oversights. One: the name storage. Two: the "empty" coast of Cinnabar. Three: the lack of error handling for the 105 empty slots.
The Rare Candy Addiction
Why did we all do it? We weren't all amateur computer scientists. We did it because MissingNo. was a godsend for anyone who didn't want to grind for 40 hours.
Seeing MissingNo. had a side effect. It glitched the sixth item in your bag, adding 128 to its quantity. If you put a Rare Candy or a Master Ball in that slot, you suddenly had an infinite supply. You could level your Charizard to level 100 in five minutes. You could catch every legendary bird without breaking a sweat. It was the ultimate "cheat" that wasn't actually a cheat code. It was a gift from the machine.
Of course, there was a price. MissingNo. would often scramble your Hall of Fame data. Sometimes the graphics for other Pokémon would look "melted" until you viewed a different menu.
Nintendo knew about it. They even officially commented on it in their Nintendo Power troubleshooting guides. They called it a "programming quirk" and warned players that it could erase their save files. Interestingly, it rarely actually deleted saves. It mostly just made the game look like it was having a stroke.
Why MissingNo. Still Matters Today
Modern gaming is different. We live in an era of Day One patches and constant internet connectivity. If a bug as massive as MissingNo. appeared in a Call of Duty or Genshin Impact update today, it would be patched within six hours. The mystery would be killed by a 200MB download.
MissingNo. represents a time when games were static. What was on the cartridge was the final version. If there was a ghost in the machine, it stayed there forever.
The Legacy of "Glitch Pokémon"
The community surrounding this bug is still massive. There are people who dedicate their lives to "Glitchology." They’ve found even weirder variants, like "’M" or "q," which are much more dangerous to your save file than MissingNo. ever was.
Check out some of the nuances that experts discuss:
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- Data Persistence: Because the Game Boy had no operating system, data stayed in the RAM until it was overwritten. This is why "glitch hunting" is even possible.
- Variable Alignment: The way the game interprets hexadecimal values (0-F) means that small typos in code lead to massive visual errors.
- Speedrunning: In "Any%" speedruns of the original games, glitches are used to manipulate memory and warp directly to the credits. MissingNo. is the gateway drug to this kind of technical play.
Even the Pokémon company has leaned into it. In later games, they introduced "Glitched" looking Pokémon like Porygon-Z or the "Ultra Beasts" that feel like thematic nods to the weirdness of the first generation. They know we remember.
Debunking the Myths
Let’s clear up some nonsense. You might have heard that MissingNo. is a "God" Pokémon or that it leads to a secret island with 1,000 Mews. No. It doesn't.
It also isn't a "Yoshi" evolution or a "Pikablu." These were all fake rumors spread on early internet forums like Geocities. MissingNo. is simply a data interpretation error. It’s the game trying to read a book in a language it doesn't understand and making up the words as it goes along. Honestly, it’s amazing the game doesn't just crash the second it appears. That it actually works—and lets you catch it—is a testament to how robust (and weird) the original game engine was.
Dealing with Glitches in Your Own Playthrough
If you’re dusting off an old Game Boy or playing on the Virtual Console, you can still encounter the King of Gaming Bugs. But you should be smart about it.
First, back up your data if you’re using an emulator. If you’re on original hardware, know that your Hall of Fame is toast the second you encounter it. That’s the "cost of doing business."
Second, don't try to trade a MissingNo. to Pokémon Yellow. While Red and Blue handle the data somewhat gracefully, Yellow was updated with better error checking. Attempting to force a glitch Pokémon into Yellow or later generations can cause much more severe stability issues.
Third, if your graphics get "scrambled" (like your trainer sprite looking like a mess of lines), just view the stats page of a "normal" Pokémon. This forces the game to reload the correct sprite data and usually fixes the visual bugs.
Actionable Steps for Glitch Hunters
If you want to experience this piece of gaming history yourself, follow these steps precisely.
- Find the Old Man: He’s in the northern part of Viridian City. Let him show you how to catch a Pokémon. This loads your name into the wild Pokémon encounter memory.
- Fly Immediately: Do not walk through tall grass. Fly directly to Cinnabar Island.
- Surge the Coast: Use a Pokémon with "Surf" to move up and down the very right-hand edge of the island. You must be half-on the land and half-on the water.
- Check Your Bag: Before the encounter, make sure the item you want to multiply (Rare Candy, etc.) is in the sixth slot from the top.
- The Encounter: When MissingNo. appears, you can run, kill it, or catch it. To get the item duplication, you just need to see it.
What to do if things go wrong:
- If the game freezes: Your cartridge might be dirty or your save battery might be dying. This isn't usually caused by the bug itself.
- If your sprites stay weird: Go to a Pokémon Center and use the PC to deposit and withdraw a Pokémon.
- If you want to "delete" MissingNo: Just release it from your box. It’s safer than keeping it if you’re worried about long-term stability.
MissingNo. is more than a mistake. It’s a window into how games are built. It’s a reminder that even in a world of strictly defined rules and code, there is room for the weird, the unexpected, and the legendary. It’s the glitch that became a character. It’s the error that everyone wanted to find. That is why it remains the undisputed king.