Dragonspark Reactor is a uncommon Artifact card from Kamigawa: Neon Dynasty (NEO), collector number 137. Current market price: $0.32 (foil $0.44), TCGplayer market prices via Scryfall.
Whenever this artifact or another artifact you control enters, put a charge counter on this artifact. {4}, Sacrifice this artifact: It deals damage equal to the number of charge counters on it to target player and that much damage to up to one target creature.