Missisingo

Missingo is a Virus or Corruption in your game. It comes out only in Pokemon Red, Blue, and Yellow. You could cheat by using Missingo, but if you catch it, your game shall froze or it'll break.

Ugh (not to you, but to missingno)

Missingno is a glitch you can get from cheating. It is a kind of Pokemon thing that has no HP and no moves, and you can encounter it in the wild. It's kind of pointless, really.

If you want to see it, take a look here:

Http://bulbapedia.bulbagarden.net/wiki/Missingno.

Or:

Http://trsrockin.com/missingno4.html

But it gets a bit confusing.

A missingNo. Is a missiong Pokemon from previous games. These games are from Pokemon green (not realsed in the UK or US) to Pokemon yellow. This "glitch" was a Pokemon that was not fully complete (many believe that it was an entai) and the "glitch" would often help the player.

This is not available anymore.

Missingno is a Pokemon you can get from an action replay cheat. It WILL make your game freeze when selected on summary and sent out to battle. I had to get a cheat that replaces the Pokemon in my party. DO NOT GET MISSINGNO! It's the last thing you want to do.

Missingo, Missingno is mixed of pieces of missing data, or incomplete data from the Pokemon Games. It is considered a virus sometimes, and is said to have erased peoples saved files, but it has not been proven that Missingno was the cause of it. It can come in many different forms, to a big block of data, to different Pokemon parts scattered together, to an invisible bulbasaur, and can also be found on super high levels ranging from 81, to 132.

Missingno, litterally meaning "Missing No" or "Missing Number". Missingno is apparently a glitch, possibly a dangerous virus, that once you catch it, your game freezes. It's made up somewhere between a shiny Bulbasaur to a block of various data. There was a glitch in Pokemon Red, Blue, and Yellow where you were able to catch Missingno where your game doesn't freeze, but catching it did infect your game.

I believe it's possible to cheat to get Missingo, but I'm not too sure about this. You need to ask that here: http://forums.supercheats.com/newtopic.php?forum=1828

Just ask about Missingno, and someone will either give you the code for Missingno, or tell you it's not possible to get it.

Learning about Missingno is actually pretty interesting, and this question was fun to answer.