Blightsteel Colossus is a mythic Artifact Creature — Phyrexian Golem card from Mirrodin Besieged (MBS), collector number 99. Current market price: $43.69 (foil $139.29), 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.