Chain Lightning is a uncommon Sorcery card from Eternal Masters (EMA), collector number 123. Current market price: $0.41 (foil $0.81), TCGplayer market prices via Scryfall.
Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.