+1: You may exile Corvo. If you do, return him to the battlfield at the beginning of your next upkeep,

-2: Create three 1/1 black Rat creature tokens with "Whenever this creature deals combat damage to a player, sacrifice it and target creatures gets -1/-1 until end of turn."

-4: Gain control of target creature until the end of your next turn. Exile Corvo until you lose control of that creature.

-7: End the turn. You may activate this ability any time you could cast an instant.