Kecleon

It can freely change its body's color. The zigzag pattern on its belly doesn't change, however.

Ability — Color Change: As long as this Pokémon is your Active Pokémon, this Pokémon is the same type as your opponent’s Active Pokémon.

Imittack: Choose 1 of the Defending Pokémon's attacks. If this Pokémon has the necessary Energy to use that attack, use it as this attack.