Color Change

 is a Pokémon ability introduced in the third generation. It changes a Pokémon's type according to the attack last used on it. It is the signature ability of Kecleon

Description
Pokémon with Color Change change type whenever they are hit by a damage-dealing move (excluding Struggle, Shadow moves and typeless Revelation Dance). They will change according to the type of move they were last hit by. Getting hit while behind a substitute does not activate the ability. Even if a Pokémon had two types before getting Color Change activated, they will change to a single type. Status conditions are infliction before Color Change activates, meaning that they could still get status conditions other Pokémon of the same type would be immune.

In the fifth generation, the final hit of a multi-strike move activates Color Change. Future Sight and Doom Desire will also now trigger Color Change when they hit (whereas before, they did not).

Pokémon with Ability

 * Kecleon

Trivia

 * Protean acts like the reverse of this ability, activates prior to each of the user's own attacks.
 * Color Change was the first Ability demonstrated in the anime.