Silent Doom is a Normal 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, Silent Doom is Unlimited.
YGOPRODeck lists Silent Doom for these formats: OCG GOAT, Duel Links, Speed Duel, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Silent Doom appears in 25th Anniversary Ultimate Kaiba Set (KC01-EN043) at Ultra Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Silent Doom is about $0.07 on Cardmarket (prices change frequently).
