Arc Reactor is a rare Artifact card from Marvel Super Heroes (MSH), collector number 310. Current market price: $1.95 (foil $2.29), TCGplayer market prices via Scryfall.
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.) This artifact enters tapped. {T}: Add {C}{C}{C}.