Aven Heartstabber 
Creature — Bird Assassin
Flying As long as there are five or more mana values among cards in your graveyard, this creature gets +2/+2 and has deathtouch. When this creature dies, mill two cards, then draw a card.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL