Trevenant, Forest Vengeance

Trample

Whenever Trevenant attacks or blocks, put a Curse counter on up to one target creature an opponent controls.
At the beginning of your upkeep, put a -1/-1 counter on each creature with a Curse counter on it, then put a +1/+1 counter on Trevenant.
Whenever a creature with a Curse counter on it dies, you draw 1 card and gain 3 life.