Missingo is a glitch in the pokemon game.Whats a glitch you say: its a mess up or some evil creater thought it might be funn it is just like a messed up blur that can corrupt your game cartridge.Anyaways to catch him you first goto virdidian forest when you get there theres an old man(the one who wouldnt move before will ask you if you know how to catch pokemon.You tell him no and he will show you how to catch them as so 
Now you must go directly to Cinnbar island and goto the right of your screen and swim half on land half on water as so 
then here we go missingo will appear. Most likely the screen will freeze with a black picture for about 5-6 seconds.When you fight him(if you want him)Be careful his defense really sucks so no powerful moves. When your fighting him he will look something like this 
when you catch he looks like this on pokemon select screen 
Kind of wierd huh? And some of the side effects of the glitch may be like this(\this really sux because you have to live with your game like this with these little sybols all over till you start over.When i caught him and got to the end and beat the elite 5 and went to pokemon hall of fame it showed pokemon in there that i didnt even own.Well anywhere here are some effects.
(Well this one is good) 
This is saying you have more of that item one good thing of missingo(this is if you beat him.)The others are bad even though i never had any major problems
