Marai the Blight Bringer

+1: Return target creature from your graveyard to your hand, then put X -1/-1 counters on target creature, where X is the chosen card's power.
-2: Destroy target creature. Return that card to the battlefield under your control with a -1/-1 counter on it.
-6: Distribute five -1/-1 counters among any number of target creatures. Then exile any number of creatures with -1/-1 counters on them.