Quicksilver Behemoth is a common Creature — Beast card from Darksteel (DST), collector number 30. Current market price: $0.24 (foil $0.55), TCGplayer market prices via Scryfall.
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.) When this creature attacks or blocks, return it to its owner's hand at end of combat. (Return it only if it's on the battlefield.)