Living in a vast subterranean lair deep inside Mount Voormithadreth in the lost land of Hyperborea (today's Greenland), Atlach-Nacha appears to by a type of enormous spider, albeit one with a face reminiscent of a human's. In this lair, The Spinner builds her web, attempting to bridge the gap between the Dreamlands and the waking world. Once it's work is complete, those who know of Atlach-Nacha's actions believe that the world will come to an end, as the monstrous denizens of the Dreamlands will be able to cross into our dimension at will.
Believed to be the ruler of all spiders everywhere, the oversized Spiders of Leng are suspected of being not only her servants, but also her children.
Thought to have travelled from Cykranosh, known as Saturn in the modern age, with fellow Great Old One Tsathoggua in the Earth's distant past, Atlach-Nacha has spent the last few millennia dwelling beneath its mountain, busy with its business of spinning webs.
- The Seven Geases (1934), by Clark Ashton Smith.