Der Nachtmahr (The Nightmare) was painted 1781 by the Swiss-born artist Heinrich Füssli (1741-1825). Neurologists, sleep medicine specialists and sleep researchers are familiar with this popular work, which became a symbol for the phenomenon of sleep paralysis. Notably, Füssli created this work decades before the first scientific description of the syndrome. Therefore, the following chapter aims to reflect the painting against the background of Füssli's biography, neuropsychological interpretations, and of pathophysiological and neurobiological considerations on sleep paralysis.