Cosmic horror speaks to perhaps one of the scariest things possible, and that is the unknown. Rooted in ideas made famous by H.P. Lovecraft, but have become much more over the years, the conceit that there are terrors beyond our understanding is unnerving. To introduce the fact that there is a universe beyond what we can see with our two eyes, and from that universe live unspeakable horrors… well, that’s a lot to swallow.
Monsters and unusual aliens of different kinds are very common in this subgenre. Sometimes it is not explained, while other times the creature may be some kind of “god,” the most famous being Lovecraft’s Cthulhu.