I hadn't played Pokemon in YEARS so I thought I'd bring down the ol' N64 system and have some fun, however I'm having a bit of an issue with my Mewtwo in Pokemon Stadium and the GB game. I caught him in the Red version of the game and before when I used to play Stadium I was able to use him in battle. Now I can't find him anywhere! It says I own him, but he's not in any of the boxes and I'm not sure what I'm doing wrong. The only thing I can think of is that's he past L100, but I don't think he is (though it has been a long time so I'm not sure).
If he is past L100, is there any way I'm able to use him? And how do I get him in a box or why can't I find him to place in a box? I did notice that, in Pokemon Stadium, when looking through my Pokedex that the Pokeball next to his name is gray. There are a few others who also have gray Pokeballs and the rest have the regular red & white Pokeballs. Does that symbolize anything? It was suggested that he could have been traded, but I've never traded with other person and if I traded him within the game it was accidental and I have no memory of doing so.
I suppose if I can't get him to work anymore I'll just have to re-catch him, right? It's all very confusing especially since I'm not as young as I used to be.
Any help would be greatly appreciated, thanks!