- "[...] but the Horla will make of men what we have made of the horse and of the ox: his chattel, his slave and his food; by the mere of his will. Woe to us!"
- ―Guy de Maupassant, The Horla
The Horla are invisible creatures believed to come from other worlds beyond the stars; which have traveled to Earth to become the next dominant species. Unreachable by human senses, they are however corporeal, and consume water and milk to survive, although never going anywhere near solid foods. They are able to enter human body and control it, giving orders that go against one's will, even though one remains conscious under their mastery.
The Horla will first invade its host during sleep, causing first physical symptoms such as fever, then psychological ones like insomnia and extreme anxiety. This is described as "feeding on the life essence" of the host, leading to believe that the Horla is partially parasitic; although its consumption of water and milk proves parasitism is not its only source of nourishment.
Based on what he learns about the Horla and their abilities, the protagonist of the story believes them to be a superior form of life, more resistant in their physical forms than humans, and thus impossible to be killed by traditional means. Whether this is true remains unconfirmed.
- Le Horla, by Guy de Maupassant (1887)