Showstopper | Magic: The Gathering
Formats Showstopper is Legal in
Official Oracle Text for Showstopper
Official Rulings for Showstopper
4/15/2013 : If another player gains control of a creature you control after Showstopper resolves, and then later that turn that creature dies, the creature's controller when it died controls the triggered ability. That player chooses a creature that one of his or her opponents controls as a target.