Aven Heartstabber is a rare Creature — Bird Assassin card from Streets of New Capenna Promos (PSNC), collector number 166s. Current market price: — (foil $0.41), TCGplayer market prices via Scryfall.
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.