A Major Upset is a Normal 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, A Major Upset is Unlimited.
YGOPRODeck lists A Major Upset for these formats: Speed Duel, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of A Major Upset appears in Ancient Prophecy (ANPR-EN080) at Short Print rarity.
Among markets shown on this page, the lowest listed snapshot for A Major Upset is about $0.11 on TCGPlayer (prices change frequently).
