Bone Devourer
From Tarkir: Dragonstorm Commander set
Bone Devourer
Creature — Dragon
2/2
Flash
Flying
This creature enters with a number of +1/+1 counters on it equal to the number of creatures that died this turn.
When this creature dies, you draw X cards and you lose X life, where X is the number of +1/+1 counters on it.
Rulings
- If Bone Devourer has +1/+1 counters put on it, and then enough -1/-1 counters are put on it to cause its toughness to be 0, X is equal to the number of +1/+1 counters it had at the time those -1/-1 counters were put on it.