Aang vs. Mewtwo
Takes place in the Earth Kingdom mountain range where Aang fought the Fire Lord.
Aang is at his absolute strongest that he has ever been, and he has no problem with killing Mewtwo.
Both know of the other's abilities beforehand.
Two rounds:
1. Normal Aang
2. Aang is in the Avatar State
Who wins and why?
Normal Aang loses. That is not even questionable.
Avatar State Aang is a bit tricky. The immense number of past lives the kid has working together exceeds the number of people Mewtwo has ever mind screwed by a good margin.
Mewtwo could telekinetically try and control Aang but someone tried that and the Avatar State overwhelmed it(but it wasn't completely TK in the traditional sense). Pure destructive capability might go to Mewtwo since he said his storm could destroy the world but that would be gradual and Aang has him topped until then.
So idk.
Originally posted by The Scenario
If you mean the Genesect one, that's actually a different Mewtwo. It's apparently a female, despite Mewtwo technically being genderless.
Don't forget how Ash completely forgot about what a Mewtwo is even though he should remember based on Mewtwo Returns and the Mirage Pokemon thing of AG.