Stumbling is a Continuous Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Stumbling is Unlimited.
YGOPRODeck lists Stumbling for these formats: GOAT, OCG GOAT, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Stumbling appears in Dark Revelation Volume 2 (DR2-EN035) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Stumbling is about $0.04 on Cardmarket (prices change frequently).
