Bone Devourer 

Creature — Dragon
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.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL