Memory of an Adversary 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, Memory of an Adversary is Unlimited.
YGOPRODeck lists Memory of an Adversary for these formats: Duel Links, TCG, OCG, Master Duel.
A listed print of Memory of an Adversary appears in Abyss Rising (ABYR-EN075) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Memory of an Adversary is about $0.28 on TCGPlayer (prices change frequently).
