S-Force Showdown is a Quick-Play 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, S-Force Showdown is Unlimited.
YGOPRODeck lists S-Force Showdown for these formats: Common Charity, TCG, OCG, Master Duel.
S-Force Showdown belongs to the S-Force archetype—use that tag when searching for engine pieces and tech options.
A listed print of S-Force Showdown appears in Blazing Vortex (BLVO-EN058) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for S-Force Showdown is about $0.02 on Cardmarket (prices change frequently).
