The H.P. Lovecraft Wiki

...[H]e described 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"

This subject contains information from the "Lovecraft Circle" Myth Cycles, and while guided by HPL are not based on his work alone. Abhoth (The Source of Uncleanliness) resides in the cavern of Y'quaa beneath Mount Voormithadreth. It is a horrid, dark gray protean mass and is said to be the ultimate source of all miscreation and abomination.

Obscene monsters constantly form in Abhoth's gray mass and crawl away from their parent. No two of Abhoth's children are alike. In general, they are complex life forms, but the majority of them are simple-minded, acting on impulse. Their forms can be anything from amorphous blobs and singular body parts, to queer humanoids and monstrous mutants. Abhoth's tentacles and limbs grab many of them, pulling them back and devouring them. Most of those that escape simply wander off, only a few of them tend to their sire's needs. Abhoth has a twisted and cynical mind, and can communicate telepathically with others near him.


Abhoth is also mentioned in Colin Wilson's "The Mind Parasites".

Abhoth is one of the Ancient Ones in the board game Arkham Horror. He is included in the Dunwich Horror expansion.

Abhoth is one of the Ancient Ones in the board game Eldritch Horror. He is included in the Under the Pyramids (Eldritch Horror Game Expansion).

In Gary Myers's short story "The Snout in the Alcove", Atal goes looking for Abhoth, believing he can gain from him the runes of the Elder Gods in order to prevent the second coming of Nyarlathotep.