Any Phase: When sealing a gate, lose 1 Stamina and 1 Sanity and return this card to the box. You do not need to make a skill check or spend any Clue tokens to seal the gate. In addition, remove one doom token from the Ancient One's doom track.
The Elder Sign is first mentioned in H. P. Lovecraft's The Dream Quest of Unknown Kadath (1926) but isn't given a description until The Shadow Over Innsmouth (1936).
The iconography of the Elder Sign used in Arkham Horror can be attributed to August Derleth's description, which first appeared in his novel The Lurker at the Threshold (1945).