That Six is a Continuous 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, That Six is Unlimited.
YGOPRODeck lists That Six for these formats: Duel Links, TCG, OCG, Master Duel.
A listed print of That Six appears in Duelist Alliance (DUEA-EN080) at Short Print rarity.
Among markets shown on this page, the lowest listed snapshot for That Six is about $0.25 on Amazon (prices change frequently).
