Annhialator Zero
killkillkillkillkill
Flail on 1 HP does 102-120 damage to neutral defence/0 IVs/0 EVs Mewtwo, dead, not win
I really think that magikarp possibly may have the upper hand. Depending on Mewtwo's level of course. A level 100 magikarp against maybe at lv 10 Mewtwo. 1 hit-KO.