Scattering Stroke is a uncommon Instant card from Lorwyn (LRW), collector number 82. Current market price: $0.30 (foil $4.39), TCGplayer market prices via Scryfall.
Counter target spell. Clash with an opponent. If you win, at the beginning of your next main phase, you may add an amount of {C} equal to that spell's mana value. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)