Whenever Galepowder Mage attacks, exile another target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.1
Illus. Jeremy Jarvis
10/1/2007: Galepowder Mage's ability can target a creature controlled by any player. It's not optional.
10/1/2007: The exiled card will be returned to the battlefield at the beginning of the end step even if Galepowder Mage is no longer on the battlefield at that time.
10/1/2007: If Galepowder Mage is the only creature on the battlefield when it attacks, its ability has no effect.