Spell Counter is a uncommon Instant card from Unhinged (UNH), collector number 46. Current market price: $3.05 (foil $24.12), TCGplayer market prices via Scryfall.
Counter target spell. Gotcha — If an opponent says "spell" or "counter," you may say "Gotcha!" When you do, return Spell Counter from your graveyard to your hand.