Alp
The Alp is the quintessential nightmare demon of German folklore, a shapeshifting malevolent spirit that sits upon the chest of sleeping people, causing the crushing sensation, paralysis, and horrifying visions now understood as sleep paralysis. The word itself is the German form of 'elf' — both derive from Common Germanic — and the Alp represents the earlier, darker aspect of elf folklore before Victorian literature romanticized elves into beneficent beings. Unlike the general 'elf' of modern fantasy, the Alp is a distinctly malefic creature that torments sleepers, rides horses to exhaustion,