- Also known as Ephialtis. Both names stem from the Greek noun ephialtes (also spelled as epialtes), which means leaper, or 'the one who jumps upon'. In Greek mythology Ephialtes, a manifestation of Pan, was considered the daimon of " nightmares. In 1900 the German classical scholar Wilhelm Heinrich Roscher (1845-1923) published an extensive account of the essence of the classical and modern nightmare in relation to Ephialtes. Referring to the nightmare-inducing experiments carried out by one of his contemporaries, Roscher asserts that "In these cases the nightmare was a peculiar bastard animal - half dog and half monkey - that did not, as before, slowly slink up to the bed, but sprang in one leap upon the breast of the victim without being previously noticed (as the result of covering the patient's face). This sudden leaping jump of the nightmare is characteristic of the majority of cases and hence the word 'Ephialtes' - 'the one who jumps up' - is very apt. The animal then remained quiet as if sleeping on his victim while the unfortunate person, out of sheer anxiety, did not dare to move until finally the animal fell down as the result of some movement executed at the height of the torture." According to Roscher, shapes in which the nightmare tends to appear are the cat, marten, hedgehog, mouse, bear, he-goat, pig, horse, tiger, snake, toad, eel, dragon, and half-dog-half-monkey. Human or humanoid figures, such as a goblin, a satyr, or a giant, are also considered possible manifestations. However, in Roscher's opinion the most frequent embodiment of the nightmare is the black poodle. Representatives of the Hippocratic School strongly opposed the popular view that the nightmare was a god, or demi-god, or wicked spirit. Instead, they considered the nightmare the equivalent of epilepsy, which they carefully addressed as 'the disease called sacred', suggesting its status as a natural rather than a supernatural disease. The term " ephialtes nocturnus is used in the older literature as a synonym for "nightmare, and " ephialtes vigilantium as a synonym for " daymare.ReferencesRoscher, W.H. (1972). Ephialtes. A pathological-mythological treatise on the nightmare in classical Antiquity. In: Pan and the nightmare.Trans-lated by O'Brien, A.V. Edited by Hillman, J. Dallas, TX: Springfield Publications.
Dictionary of Hallucinations. J.D. Blom. 2010.