Clash of Elements is a uncommon Instant card from Reality Fracture (FRA), collector number 126. Current market price: $0.19 (foil $0.27), TCGplayer market prices via Scryfall.
Choose target nonland permanent. Its owner may put it on top of their library. If they do, Clash of Elements deals 2 damage to them. If they didn't put the card on top of their library, they put it on the bottom.