When a Pokémon with this Ability is hit by a damage-dealing move (except Struggle and Shadow moves), Color Change will change the Pokémon's own type to the type of the move that it was hit by. Color Change does not activate if the Pokémon's substitute is hit.
Even if the Pokémon with Color Change has two types, it will only have a single type after the effect is applied. If a Pokémon with this Ability is hit by Weather Ball during shadowy aura, it will become Normal-type.
Status conditions are inflicted before Color Change activates. As a result, even if Color Change would make the Pokémon become a type that is immune to the status condition, the Pokémon can still be afflicted with the status condition; for example, a Pokémon with Color Change that is hit by Poison Sting has a chance to be poisoned before it becomes Poison-type.
Generation V onward
Color Change now activates after the last hit of a multi-strike move.
Future Sight and Doom Desire now activate Color Change when they hit (they do not activate Color Change when used).
Color Change will not activate when the Pokémon is hit by a typeless Revelation Dance.