Nirti,Twilight Mistress

+1: Put a +1/+1 counter on target creature you controll. Next put a -1/-1 counter on target creature an opponent controlls.
-2: Create a 3/3 green and black Wolf Spirit creature token with Shadow onto the battlefield.
-7: Destroy each creature without Shadow. Ech player looses 1 life for each creature under his or her controll destoryed that way.