Batterskull is a mythic Artifact — Equipment card from Double Masters (2XM), collector number 356. Current market price: $10.72 (foil $11.45), TCGplayer market prices via Scryfall.
Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.) Equipped creature gets +4/+4 and has vigilance and lifelink. {3}: Return this Equipment to its owner's hand. Equip {5}