Tarrian's Soulcleaver is a rare Legendary Artifact — Equipment card from The Lost Caverns of Ixalan (LCI), collector number 264. Current market price: $4.83 (foil $5.39), TCGplayer market prices via Scryfall.
Equipped creature has vigilance. Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature. Equip {2}