Research Findings
~ Documented observations and analysis ~
The Four Forms of MissingNo
Through extensive testing across multiple cartridges, we have confirmed that MissingNo manifests in four distinct visual forms. Each form is tied to specific index numbers in the games internal pokemon database.
Form 1: The L-Block
This is the form most people think of when they hear "MissingNo." It appears as a collection of scrambled pixels arranged in a rough backwards-L shape. The pixels are actually being pulled from random sections of video memory. What your seeing is litterly the games graphics data being misread and displayed as a pokemon sprite.
The L-Block form corresponds to most of the empty index slots. Each one is technicaly a "different" MissingNo but they all look the same because the game handles them all the same way. It reads garbage data from VRAM and tries to render it as a 56x56 pixel sprite.
Form 2: The Ghost
This form uses the ghost sprite from Pokemon Tower, the same one you see before getting the Silph Scope. Its index 0 in the pokemon database, which is intresting because index 0 is typically used as a "null" value in programing. Its like the game is saying "there is no pokemon here" but then trying to display it anyway.
We believe this form is significent because it suggests the developers were aware of the empty slot problem. Using the ghost sprite, a sprite that literaly represents "something that shouldnt be visible," as the placeholder for index 0 cant be a coincidence. Or can it?
Form 3: Kabutops Fossil
Index 182 displays the Kabutops fossil skeleton sprite from the Pewter City museum. This is one of the more mysterious forms because theres no obvious technical reason why a fossil sprite would be assigned to an empty index slot. The fossil sprites are stored in a completley different part of the ROM than the pokemon sprites.
One theory we've been working on: the fossil sprites were originally ment to be used for some kind of fossil-resurrection minigame that got cut from the final release. The index slots they occupy might have been reserved for "fossil forms" of pokemon that never made it into the game. This is unconfirmed but we think its a strong possibility.
Form 4: Aerodactyl Fossil
Index 183, right next to the Kabutops fossil. Same mystery applies. Why are museum display sprites being used for empty pokemon slots? The placement of these two fossil forms next to eachother in the index table strongly suggests they were intentionaly placed there, not randomly assigned.
The Connection to 'M (00)
'M (sometimes written as 'M Block or pokemon 00) is MissingNos "cousin," another glitch pokemon found through the same method. While MissingNo occupies empty index slots, 'M specifically occupies index 0 in a different context.
Key differences between MissingNo and 'M:
| Property | MissingNo | 'M (00) |
|---|---|---|
| Can be caught | Yes | Yes |
| Can evolve | No | Yes, into Kangaskhan! |
| Stable in PC | Mostly | Can corrupt box data |
| Duplicates items | Yes (6th slot) | Yes (6th slot) |
| Freezes game | Rarely | Sometimes |
The fact that 'M evolves into Kangaskhan has led to one of the most persistant theories in our field: that MissingNo and 'M are remnants of a scrapped pokemon evolution chain that was removed late in development. Kangaskhan has no pre-evolution in Gen I (it didnt get one until much later with Cubone theories), and the connection between an "empty slot" pokemon evolving into a fully-formed Kangaskhan is... suspicious.
We dont have definitive proof of this theory. But we have enough circumstantial evidence that I personaly believe it warrants continued investigation.
Other Glitch Pokemon of Note
MissingNo is the most famous glitch pokemon, but Generation I contains several others worth mentioning:
- LM4 - A glitch pokemon that knows Water Gun twice and Sky Attack. Displays garbled sprites that are different every time you encounter it.
- Q (Glitch Pokemon EF) - One of the more dangerous glitch pokemon. Can corrupt save data if caught and deposited into the PC. DO NOT catch this one.
- PkMn (various) - Multiple glitch pokemon that display fragments of text and interface elements as their sprites. Some researchers believe these contain scraps of debug menus that were compiled into the final ROM.
- Female symbol glitch pokemon - A glitch pokemon whose name displays as the female gender symbol. It has real pokemon stats and can actually battle, making it one of the more "stable" glitch entities.
A full catalog of all 105 glitch pokemon in Gen I is beyond the scope of this website (maybe someday), but I wanted to note that MissingNo exists within a much larger ecosystem of undocumented entities. Its not alone in there.