Dynavolt Tower is a rare Artifact card from Kaladesh Promos (PKLD), collector number 208s. Current market price: — (foil $2.24), TCGplayer market prices via Scryfall.
Whenever you cast an instant or sorcery spell, you get {E}{E} (two energy counters). {T}, Pay {E}{E}{E}{E}{E}: This artifact deals 3 damage to any target.