Colossus Hammer is a rare Artifact — Equipment card from Secret Lair Drop (SLD), collector number 736. Current market price: $16.03 (foil $17.61), TCGplayer market prices via Scryfall.
Equipped creature gets +10/+10 and loses flying. Equip {8} ({8}: Attach to target creature you control. Equip only as a sorcery.)