The general theme of stories written as part of the Cthulhu Mythos, Lovecraft-authored or no, is Madness. A General theme in the stories is eldritch creatures of questionable reality and nature, such as the amorphous shoggoths, the madness-inducing Cthulhu, the alien and invisible Dunwich Horror, and even so far as the reality-warping power of Nyarlathotep. The Cthulhu Mythos pioneered an entirely new type of horror with it's strange, enticing themes; Lovecraftian horror. Notable examples of lovecraftian horror not written by H.P. himself are The King in Yellow by Robert W. Chambers, Dagon's Bell by Brian Lumley, and A Study in Emerald by Neil Gaiman.