Arguably one of the most infamous video game glitches of all time, MissingNo. is a numberless Pokémon that appears on the coasts of Cinnabar Island, and the Seafoam Islands in Pokémon Red and Blue. MissingNo. will often appear at extremely high levels above the game limit of 100, despite being extraordinarily weak. Along with MissingNo., a seemingly random selection of other Pokémon, sometimes above level 100, may also appear. The glitch also allows players to multiply the quantity of any item sitting in the 6th position of the player's Item bag.
MissingNo. can be encountered by first speaking with the old man in Viridian City and asking him to show you how to catch a Pokémon. After this, when surfing along the Eastern coast of Cinnabar or Seafoam, MissingNo. will appear as a random battle, so long as the player has not entered any other wild Pokémon areas after talking to the Old Man. Upon capture, MissingNo. may distort in-game graphics, sometimes leading to a game crash or corruption of the save file.
A very similar glitch know as 'M can also be found in the Pokémon Red and Blue games.
Pokémon Near MissingNo.
Another useful side-effect of the MissingNo. glitch is that while you are surfing along the Eastern coast of Seafoam Island (and possibly on other coasts) looking for MissingNo., there is also a very good chance that you will encounter Pokémon from the last area you were in before flying to Viridian City to talk to the old man.
Why this is so useful is because it means you are able to encounter Safari Zone Pokémon outside of the Safari Zone, allowing you to battle them and capture them with regular Poké Balls, including Master Balls. To do this you would fly to Fuchsia City, enter the Safari Zone, then leave and fly to Viridian to talk to the old man. Then fly back to Fuschia, surf SouthWest to the Eastern cost of the Seafoam Islands. While surfing along the coast, you will now encounter Pokémon from the Safarai Zone, as well as MissingNo and others.
This method can also be used to find wild Pokémon that normally reside within almost any other area in the game. Unlike catching MissingNo., catching these mislocated Pokémon will not have a negative impact on the stability of your game. It is also theoretically possible that this will work without talking to the Old Man in Viridian, but you would not be able to find MissingNo. or any other Pokémon over level 100 there.
MissingNo. can be used to add 128 to the quantity of any item you currently have in your pack. To do so, follow these steps:
- Open your bag and find your desired item
- Move that item to the 6th slot from the top using the Select button.
- Exit the bag and perform the MissingNo. glitch.
- After encountering MissingNo., defeat it or run away (as opposed to capturing it)
- After that is done, check your bag, and you will find that your desired item now has an odd symbol next to it as well as a number. Because there are only two spaces for numbers, the symbols are used to represent a digit higher than 9, meaning that you have more than 99 of an item. Different symbols represent different >9 digits. After performing the MissingNo. item glitch, you will have 128 more of the item you chose, with a possible cap of 255.
This is an extremely useful exploit that can be used to provide the player with a limitless supply of rare or unique items such as the Master Ball and Rare Candy.
Why The MissingNo. Glitch Occurs
It has to do with programming variables in the game code. For most variables on Game Boy games, the fewest possibilities for the variable is 256 (HEX 100), labeled 0 to 255 (HEX 00 to FF). This goes for most variables in Pokemon R/B/Y, including ones for all the Pokémon lookup slots. However, only 151 Pokemon exist in R/B/Y. So, if there are 255 possibilities, and only 151 slots were defined by the programmers, what do the other 104 slots have? Glitches. And so, MissingNo. was created.
When creating the map for what Pokemon will appear where in the game, the designers made a crucial error. The 1-square-wide strip of water on the right side of Cinnabar and Seafoam Islands was programmed to be a place where wild Pokémon CAN appear. However, they forgot to define WHICH Pokémon can appear there. What this means is that the previous settings for "what Pokemon can appear" will remain from the last location in which the player encountered Pokémon, meaning that if the player went to, say, the Safari Zone, and then came to this blank area, the player would still be encountering Safari Zone Pokémon.
However, this would still never yield encounters with glitch Pokémon. This is where the Old Man and his Pokémon-catching tutorial come in. For the purposes of the tutorial, the player's name is temporarily changed to "Old Man" while he demonstrates catching a Weedle. During this time, the name "Old Man" occupies the space where the variables for the player's name would usually be kept, and so the player's name must be moved someplace else during that time. What the designers chose to do was have the player's name stored in the place where the variables for which Pokémon can appear, and what the level those Pokémon will be, would usually be kept.
Normally, this would not present any problems, as this data would simply be overwritten the instant the player stepped into tall grass, or any other area with wild Pokémon in it. However, if the player instead, surfs along the Cinnabar or Seafoam coasts, the game will use the player's name to determine which Pokémon will appear, which causes a seemingly random mishmash of Pokémon at wildly ranging levels, as well as MissingNo., to appear. This explains why each player's experience with the MissingNo. glitch is different: Because each player's name is different.
Breakdown of the Player's Name's Effect on the Glitch
The level of MissingNo. and the other Pokémon the player will find through the use of this glitch are determined by the 2nd, 4th, and 6th letters of the players name. Take the numerical equivalent (A=1, B=2, C=3, etc.) of those letters, and add 127 for uppercase or 159 for lowercase.
For the player name 'Harold', Pokémon levels would be determined by a, o, and d.
a = 1 plus 159 = 160
o = 15 plus 159 = 174
d = 4 plus 159 = 163
Also, at the end of your name, the game inserts an 80 (HEX 50) to designate "End of Name". Because of how the variables are used, this means that one of the levels your MissingNo. can be is always 80.
This means the possible levels of Pokémon to appear as for the name 'Harold' will be 160, 174, 163, and 80.
In addition, here are the values of most of the other symbols that can be used in a name:
( = 154, ) = 155, : = 156, ; = 157, [ = 158, ] = 159, 'pk' = 209, 'mn' = 210, ? = 239, . = 242, ? = 245, and x(multiplication sign) = 241
Pokémon That Will Appear
The Pokémon that will appear is determined by the 1st, 3rd, 5th, and 7th letters of the player's name:
Using the Pokémon list below, and the level example above, here is what a player with the name Harold will encounter:
So a player with the name 'Harold' will encounter MissingNo., Squirtle, and Aerodactyl at levels 160, 174, 163, and 80. Note: The player will also encounter other Pokémon, leftover from whichever area they visited before talking to the Old Man, such as the Safari Zone.
*(Note: other, non-letter characters will also produce pokemon, not listed here)
MissingNo. in Pokémon Yellow
MissingNo. cannot be caught using the original method, in Pokémon Yellow. Instead, replicating the infamous "Mew Gitch" from Red and Blue will sometimes yield a MissingNo. This version of the glitch is slightly different, baring a different sprite and a Speed stat of 0. Its types are listed as Normal/99||9. It starts with Pay Day, Bind, and Water Gun and does not learn any other attacks via level.