Proof of Powerlessness 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, Proof of Powerlessness is Unlimited.
YGOPRODeck lists Proof of Powerlessness for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Proof of Powerlessness appears in Raging Battle (RGBT-EN076) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Proof of Powerlessness is about $0.26 on Cardmarket (prices change frequently).
