Exile target creature with the greatest power among creatures on the battlefield. (If two or more creatures are tied for greatest power, target any one of them.)
"Let all witness the fate of those who defy me."
—Crovax
It can only target a creature with the greatest power. This means you pick such a creature on announcement, and if that creature is not still the one with greatest power on resolution, then this spell doesn’t resolve since its target is illegal.
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.