Cauchemar is the French word for “nightmare”, and it is also the name of this species of vampiric demon or witch.

At night the cauchemar shape-shifts into either an INCUBUS or a SUCCUBUS and slips into the bed of what it perceives to be an evil person. Then it has sexual relations with him, enslaving the person to its will and draining him of some of his life and sexual energy (see ENERGY VAMPIRE). In the morning, the victim will awake with drool descending from either side of his mouth and with evidence of having experienced a nocturnal emission. Other signs include feeling overly tired and suffering leg cramps.

To prevent the cauchemar from attacking, a person can place some SALT under his pillow or dried beans or stones under his bed every night. A broom propped in the corner will offer protection, as will sleeping on one’s stomach. Saying prayers before going to bed and keeping religious items in the room will prevent it from entering. If all else fails, one can put screens on the windows.

If the cauchemar cannot be prevented from entering the room and attacking, it is vital that no one ever so much as touches the victim during one of the assaults. To do so can cause the cauchemar to kill the victim as it flees.

Source: The Living Age, vol.4, 495; Mackay, Gaelic Etymology, 305; Masters, Eros and Evil, 181; Rose, Spirits, Fairies, Gnomes, 212