Gorag, Grave Consumer

Flying
When Gorag, Grave Consumer enters the battlefield, each opponent mills three cards (To
mill a card, a player puts that many cards from the
top of their library into their graveyard)
Whenever a creature dies or is put into a
graveyard from anywhere, put X +1/+1 counters
on Gorag, where X is the mana value of the
creature.