Almost always goes last; if an opponent strikes with a Physical attack before the user's turn, the user retaliates for twice the damage it had endured.
This move is temporarily replaced by the target's last move; the replacement move will have 5 PP and become part of the user's moveset until the user switches out or the battle ends. Mimic copies attacks even if they miss or the user has immunity toward their type; it cannot copy itself, Struggle, Transform, Sketch, Metronome or moves that the user already knows, and it will fail if the target has yet to use a move.