When Marked for Death is revealed, if a copy of Mockingbird is already under a player’s control who is not Clint…

The Clint Barton player must search for Mockingbird in their hand, deck, discard pile, and play area, though cannot place their Mockingbird under Marked for Death as there is already a unique character in play with the same title/ subtitle (shuffle after searching a deck). However, when Marked for Death is defeated, any copy of Mockingbird in play (even one controlled by another player) is returned to its owner’s hand.