Talon of Pain is a uncommon Artifact card from Darksteel (DST), collector number 150. Current market price: $0.28 (foil $2.22), TCGplayer market prices via Scryfall.
Whenever a source you control other than this artifact deals damage to an opponent, put a charge counter on this artifact. {X}, {T}, Remove X charge counters from this artifact: It deals X damage to any target.