This sound is from Mewtwo Soundboard

Actress Reiko Takashima voiced a second, unrelated Mewtwo in the Pokémon anime special Mewtwo Prologue to Awakening and its direct sequel, Pokémon the Movie Genesect and the Legend Awakened this second Mewtwo is voiced by actress Miriam Pultro in the English dub.
See also: Pokémon: The First Movie, Pokémon: Mewtwo Strikes Back—Evolution, Pokémon: Mewtwo Returns, Pokémon the Movie: Genesect and the Legend Awakened, Mew (Pokémon), and List of Pokémon films.