Broken Concentration is a uncommon Instant card from Shadows over Innistrad (SOI), collector number 50. Current market price: $0.12 (foil $0.56), TCGplayer market prices via Scryfall.
Counter target spell. Madness {3}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)