Story by August Derleth published in The Mask Of Cthulhu and later featured in The Hastur Cycle. Derleth ties Hastur deeply into the Cthulhu Mythos as a Great Old One and introduces the controversial Elemental Theory of the Great Old Ones. The story assumes that the writings of H.P. Lovecraft and Robert W. Chambers exist in the world in which the story takes place. It implies a connection between Hastur and Shub-Niggurath. The story is set in Arkham. It also ties the dread cry of Tekeli-li into the Yellow Mythos.