Wave-Motion Cannon 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, Wave-Motion Cannon is Unlimited.
YGOPRODeck lists Wave-Motion Cannon for these formats: GOAT, OCG GOAT, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Wave-Motion Cannon appears in Champion Pack: Game Five (CP05-EN004) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Wave-Motion Cannon is about $0.10 on Cardmarket (prices change frequently).
