Craterhoof Behemoth
Avacyn Restored — mythic
Creature — Beast
Craterhoof Behemoth rulings:
2017-03-14: The value of X is determined only as Craterhoof Behemoth’s triggered ability resolves, potentially including Craterhoof Behemoth itself. It won’t change later in the turn if the number of creatures you control changes.
2017-03-14: Craterhoof Behemoth’s triggered ability affects only creatures you control at the time it resolves. It won’t affect creatures that come under your control later in the turn.