Blightsteel Colossus is a mythic Artifact Creature — Phyrexian Golem card from Double Masters (2XM), collector number 235. Current market price: $40.90 (foil $49.95), TCGplayer market prices via Scryfall.
Trample, infect, indestructible If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.