Overzealous Aethermage

Mentality -- When Overzealous Aethermage enters the battlefield, reveal the top card of your library. If it's a white card, exile target creature until Overzealous Aethermage leaves the battlefield. Otherwise, return target creature to
its owner's hand. Then shuffle your library.
Her tutors at the academy were often dismayed by
her approach to removing obstacles.