What is MissingNo., and is it really dangerous to your game?Fiction
In-universe lore. Claims are judged against the fiction's own canon, not the real world.
MissingNo. is the infamous glitch "Pokemon" that appears when Generation I's Red, Blue, and Yellow misread stray data as a species, and it arrives wrapped in creepypasta claiming it bricks cartridges or wipes saves. In truth it is the games' handling of an undefined species index, and the corruption it causes, though real, is reversible.
6 established, 3 disputed, 2 debunked, 2 unresolved. We do not pick an answer; the evidence places each claim. How we decide
18 citations from 2 independent sources - 16 echo the same voices and count once. Graded C2-D2.
Added 3 Jul 2026 - updated 9 Jul 2026 - canon current as of 9 Jul 2026
What the four states mean
- Establishedsupported, uncontested
- Disputedcredible sources disagree
- Debunkedrefuted by the evidence
- Unresolvedno settled answer
Established 6supported, uncontested
MissingNo. is not a designed creature but Generation I's handling of an undefined species slot, a glitch Pokemon listed as Pokedex number 000.▰▰▱▱▱ likely1 source
Supports- Bulbapedia describes MissingNo. as a glitch Pokemon occupying undefined index slots in the Generation I games, catalogued as number 000 and made of placeholder or leftover data rather than a real species.MissingNo. - Bulbapedia analysis
MissingNo. is produced by the Old Man / Cinnabar coast glitch: certain areas do not overwrite an encounter buffer, so the player's own name is left there and misread as wild-Pokemon data.▰▰▱▱▱ likelysummary-sourced1 source
Supports- After watching the Old Man's catching demonstration and then surfing the east coast of Cinnabar Island, the game reuses leftover buffer data because that area never overwrites it, and the player's name is interpreted as the species to encounter.MissingNo. - Wikipedia summary
Encountering MissingNo. really does multiply items: it adds 128 to the quantity of the sixth item in the player's Bag, unless that stack already exceeds 128.▰▰▱▱▱ likely1 source
Supports- Bulbapedia states that MissingNo.'s appearance in battle triggers the item duplication glitch, increasing the number of items in the sixth Bag slot by 128 when that slot holds fewer than 128.MissingNo. - Bulbapedia analysis
The real corruption is graphical: MissingNo.'s oversized sprite overflows into save RAM holding Hall of Fame data, and its "seen" flag shares a bit with the sixth Bag slot's quantity, scrambling the Hall of Fame display.▰▰▱▱▱ likely1 source
Supports- Bulbapedia explains that the Hall of Fame becomes corrupted because the bit recording MissingNo. as seen in the Pokedex overlaps the first bit of the sixth Bag slot's quantity, and its glitched sprite spills into the save memory where Hall of Fame data lives.MissingNo. - Bulbapedia analysis
Nintendo officially acknowledged MissingNo. in the May 1999 Nintendo Power, calling it a programming quirk and not a real part of the game.▰▰▱▱▱ likelysummary-sourced1 source
Supports- In the May 1999 issue of Nintendo Power, Nintendo of America described MissingNo. as a programming quirk that is not a real part of the game.MissingNo. - Wikipedia summary
MissingNo. has several distinct appearances, including the backwards-L block of pixels in Red and Blue, plus Ghost, Kabutops-fossil, and Aerodactyl-fossil forms, and a separate normal form in Yellow.▰▰▱▱▱ likely1 source
Supports- Bulbapedia lists five forms of MissingNo.: the default Red/Blue block sprite, a distinct Yellow form, the Kabutops Fossil and Aerodactyl Fossil sprites, and the Ghost sprite from the Pokemon Tower.MissingNo. - Bulbapedia analysis
Disputed 3credible sources disagree
Whether MissingNo. is truly "a Pokemon" is contested: it carries a Pokedex number and even a type, yet it is undefined data rather than an intended species.▰▰▰▱▱ roughly even chance1 against2 points
Supports- MissingNo. behaves like a species in some respects, appearing at Pokedex number 000 and even bearing the unused Bird type alongside Normal, which fans cite as evidence it is a kind of Pokemon.MissingNo. - Wikipedia summary
Against- Bulbapedia frames MissingNo. as a glitch Pokemon built from leftover or undefined data, not a creature Game Freak designed, so calling it a genuine species is disputed.MissingNo. - Bulbapedia analysis
MissingNo. is routinely conflated with 'M, but they are technically distinct glitch Pokemon that merely share the same sprite and Pokedex number 000.▰▰▰▱▱ roughly even chance1 against2 points
Supports- Because 'M and MissingNo. display the same sprite and both show as number 000, players often treat them as one and the same glitch.'M (Pokemon) - Bulbapedia analysis
Against- Bulbapedia stresses they are different entities with different internal index numbers: 'M can evolve into Kangaskhan or Clefairy and appears only under non-default player names, whereas MissingNo. cannot, so the two are not interchangeable.'M (Pokemon) - Bulbapedia analysis
MissingNo.'s exact form and how it is triggered differ by version, so accounts of it vary between Red/Blue and Yellow rather than being a single fixed encounter.▰▰▰▱▱ roughly even chance1 against2 points
Supports- Bulbapedia documents a separate Yellow sprite and notes the glitch's index behaviour varies, so the specific form encountered depends on the version and the exact method used.MissingNo. - Bulbapedia analysis
Against- Which glitch Pokemon actually appears also depends on the player's name and encounter route, meaning the same steps do not always yield an identical MissingNo. across cartridges.'M (Pokemon) - Bulbapedia analysis
Debunked 2refuted by the evidence
The popular creepypasta that MissingNo. permanently bricks the cartridge or erases your save is false; its effects are reversible and no data is destroyed.Refuted by
In practice the graphical corruption is only temporary: Bulbapedia notes that viewing the stats screen of any non-glitch Pokemon removes the effects, and resetting the console also clears them, so the save is never actually destroyed.
refuted1 against2 pointsThe claim rested on- The urban legend, echoed in early magazines and fan lore, warned that any contact with MissingNo. could wipe your game file or ruin the cartridge for good.MissingNo. - Wikipedia summary
Refuted by- In practice the graphical corruption is only temporary: Bulbapedia notes that viewing the stats screen of any non-glitch Pokemon removes the effects, and resetting the console also clears them, so the save is never actually destroyed.MissingNo. - Bulbapedia analysis
Nintendo Power's own advice about MissingNo. was inaccurate: it suggested releasing the glitch and possibly restarting the game to fix the graphics, when simply viewing a normal Pokemon's stats resolves it.Refuted by
That advice was wrong: releasing MissingNo. does not fix the graphics and no restart is needed, since viewing the Pokedex or stats page of any legitimate Pokemon clears the corruption.
refuted1 against2 pointsThe claim rested on- Nintendo Power warned that contact with MissingNo. could erase the game file or disrupt graphics, implying a player might have to restart from the beginning to clear the scrambled display.MissingNo. - Wikipedia summary
Refuted by- That advice was wrong: releasing MissingNo. does not fix the graphics and no restart is needed, since viewing the Pokedex or stats page of any legitimate Pokemon clears the corruption.MissingNo. - Bulbapedia analysis
Unresolved 2no settled answer
Whether MissingNo. is canon in any sense is unresolved: fans rationalize it through theories tying it to Kangaskhan and Cubone, but it was never an intended species.▰▰▱▱▱ likelysummary-sourced1 source
Supports- Wikipedia notes that fans have tried to rationalize MissingNo. as canonical, floating theories that connect it to Kangaskhan and Cubone, and its unused Bird type feeds that speculation.MissingNo. - Wikipedia summary
Official sources give MissingNo. no standing as a real species, yet it was never patched out of Generation I and has been affectionately referenced in later games, leaving its cultural status ambiguous.▰▰▱▱▱ likelysummary-sourced1 source
Supports- Despite Nintendo calling it not a real part of the game, MissingNo. endured as one of gaming's most famous glitches and was later homaged in titles such as Vampire Survivors and The Binding of Isaac: Rebirth, so its status sits between error and icon.MissingNo. - Wikipedia summary
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