Explores a distinctive form of nocturnal fright: the 'night-mare', or incubus - the state of consciousness between sleep and wakefulness, when you are unable to move or speak and may experience vivid and often frightening hallucinations. This focuses on the ways in which night-mare attacks have been experienced and interpreted throughout history and across cultures and how, in a unique example of the effect of nocebo (placebo's evil twin), the combination of meaning and biology may result in sudden nocturnal death.