MissingNO is a glitched pokémon that appears in Pokémon Red/Blue/Yellow versions. Not everyone has heard of it, yet alone, encountered it in their game. I know that hardly anybody plays these versions anymore, but if you have seen it, feel free to discuss how and where!
And just for reference, this is what MissingNO looks like:
MissingNO was created in haste when the game makers were running low on production time. The game took longer to finish than they expected, and the release date was coming too fast. MissingNO was supposed to be Ho-oh. Remember the 1st episode of Pokemon when Ash saw Ho-oh? Ho-oh was meant to be the 4th of the legendary birds (Articuno, Zapdos, Moltres). Ho-oh was supposed to be more of a "rainbow" bird, as opposed to being the Sun bird. If it weren't for MissingNO, we wouldn't have Lugia and a lot of stuff might be different in pokemon.
Although, i caught missingno. I looked at its icon and it was a magicarp. Then when i walked into the pokemn centre, it turned into a trainer. I fought with it and it had sky drop and afew other moves.
Ive done research and found out its not Ho-oh MissingNo can evolve into Rydon and Kangaskan. But nothing is known why MissingNo evolved into that but before they released the game they were planning of having Marowak evolve int Kangaskan. Take a look at the child in Kangaskans pouch and then Cubone. The same. But they did not include this in the game as it seemed scary for children. A Cubone tearing out Kangaskans bone Scary