Lovecraft hits both sweet spots in “The Shadow Out of Time,” of course (I reread thanks to your pointer a few months ago, btw… thanks!), and in many horror or horror-tinged works the assumption is often that some insectoid–or worse–being or beings are taking human form and walking among us. Zombies also hit both, albeit crudely (when horror misses the mark it’s mere comedy) as their similarity to living humans remains and falls away simultaneously–a key, perhaps, to their cultural omnipresence these days. And in rough tangential relation to the recent atheism post, the “soul” seems to be the litmus (or perhaps Turing) test–no soul or loss/devouring/destruction/assimilation of individual soul=horror (perhaps, too, why mystical sects and cults that emphasize the collective/obliterate the individual can seem so Pol Potty-horrifying, transferring millennial religious coding to the political… [heaven is a hell on earth])?

While horror is a well established genre in literature and cinema, the only example of effective “horror music” that comes to mind right now is the track “Under the House” by Public Image Limited. In a radio interview, Lydon mentioned that the track was inspired by the old Manor Studios where the “Flowers of Romance” album was recorded. “I thinks it’s haunted,” he announced emphatically, and when listened to alone in the dark the track can indeed evoke a chilling sense of the ontological “wrongness” of the undefined, unspeakable “it” that “went under the house.”
A bit like the chills one gets from a solitary reading of William Hope Hodgson’s “The House on the Borderland” (a seminal influence on Lovecraft apparently).