Gnaw to the Bone 
Instant
You gain 2 life for each creature card in your graveyard.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL