Yeah, I'm a bit confused about this too. "The user immediately uses the last move that the opponent used to target the user. It will fail if the target did not select a move in the turn prior to this one, or if the target switches out, or if the last move used by the target was Mirror Move. If used when the target is charging for a two-turn attack, then Mirror Move will copy the move used directly before that move." Maybe it's because of Prankster ? Sawsbuck would die to Hurricane though, so it's still not much of a safe switch-in.