Creatures that come under your control after Showstopper resolves won’t have the ability.
15-04-2013
wotc
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 their opponents controls as a target.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.