Thorna and Twigtooth

Legendary Creature — Giant Treefolk6/7

Thorna and Twigtooth enters with two -1/-1 counters on it. Whenever Thorna and Twigtooth attacks, remove all counters from target creature you control. Each opponent loses X life, you gain X life, and the topmost creature card in your library perpetually gets +X/+X, where X is the number of counters removed this way.

Not legal in Commander