Dead-Iron Sledge is a uncommon Artifact — Equipment card from Mirrodin (MRD), collector number 162. Current market price: $0.23 (foil $1.10), TCGplayer market prices via Scryfall.
Whenever equipped creature blocks or becomes blocked by a creature, destroy both creatures. Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)