Such superstitions go back to Anglo-Saxon elves, whence come Old English nouns as aelf-adl ("elf-disease"), aelfsiden ("elf-influence," some type of delirium), aelfsogooa ("elf-sucking," a kind of diabolic possession), ylfa gescot ("elf-shot," an internal sharp pain), and the adjective ylfig ("affected by elves," i.e.