"The Source of Uncleanliness"
When 3 Mysteries have been solved, investigators win the game.
The players have 14 spaces on the Doom counter before Abhoth awakens.
Abhoth lies deep within the heart of Mount Voormithadreth. There, from the cesspit of Y'quaa, it sends forth its revolting children, extending its reach across the Earth.
Set aside 8 Cultist Monsters and all Abhoth Special Encounters.
A pool of filth from which horrible monstrosities emerge. Can communicate telepathically. In the story "The Seven Geases", refuses to devour a supplicant out of fear of indigestion.
"Then, in that reeky twilight... he descried a sort of pool with a margin of mud that was marled with obscene offal; and in the pool a grayish, horrid mass that nearly choked it from rim to rim.
Here, it seemed, was the ultimate source of all miscreation and abomination. For the gray mass quobbed and quivered, and swelled perpetually; and from it, in manifold fission, were spawned the anatomies that crept away on every side through the grotto. There were things like bodiless legs or arms that flailed in the slime, or heads that rolled, or floundering bellies with fishes' fins; and all manner of things malformed and monstrous, that grew in size as they departed from the neighborhood of Abhoth. And those that swam not swiftly ashore when they fell into the pool from Abhoth, were devoured by mouths that gaped in the parent bulk."
—Clark Ashton Smith, The Seven Geases
Cavern of Y'quaa, beneath Mount Voormithadreth, the tallest peak in the Eiglophian Mountains, spanning the middle of Hyperborea (north of the Arctic Circle)
The Seven Geases, Clark Ashton Smith, 1934.