The chant comes from H. P. Lovecraft and his story The Call of Cthulhu, where cultists repeat Ia Ia Cthulhu fhtagn, meaning Cthulhu waits dreaming, as they worship the sleeping Great Old One. The phrase entered wider horror culture through books, films, games and tabletop roleplaying, where it became a shorthand for forbidden knowledge and cosmic horror. Online, creators shortened it to the two-word call and use it in short videos, edits and memes whenever they want an instant signal that something ancient, powerful and dangerous is stirring.