Smashing Horn is a Counter Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Smashing Horn is Unlimited.
YGOPRODeck lists Smashing Horn for these formats: Duel Links, TCG, OCG, Master Duel.
A listed print of Smashing Horn appears in Generation Force (GENF-EN089) at Secret Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Smashing Horn is about $0.66 on TCGPlayer (prices change frequently).
