What about 'em?
Oh, for the love of...do you understand how psychic power works? We're not talking movesets, and stats, and hold items and crap here. Mewtwo would blow up Frieza's head the moment they locked eyes. He talks to you without moving his mouth because he's inside your mind. Do you really think Frieza's going to know how to counter something like that? Mewtwo can teleport, can put up shields powered by its mind. As long as Mewtwo's mind remains intact, those shields aren't going down, and if you can't get through the shields, how are you going to damage its mind? The only reason Mewtwo can be bested in Pokemon is for gameplay reasons. In a universe full of, for all intents and purposes, gods, capable of creating landmasses, seas, with control over life, death, space, time, and the universe itself, Mewtwo is the ultimate. Frieza wouldn't stand a damn chance in HFIL.
But seriously, this is just sad. They really need to give us some details here, so we actually have something to discuss.