Darksteel Colossus is a rare Artifact Creature — Golem card from Darksteel (DST), collector number 109. Current market price: $5.26 (foil $25.43), TCGplayer market prices via Scryfall.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.) Indestructible (Damage and effects that say "destroy" don't destroy this creature.) If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.