Possessed Aven 
Creature — Bird Soldier Horror
Flying
Threshold — As long as seven or more cards are in your graveyard, this creature gets +1/+1, is black, and has "
, 
: Destroy target blue creature."
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL