The Nightmare is a 1781 oil painting by Anglo-Swiss artist Henry Fuseli (1741–1825).
The Nightmare was first displayed at the annual Royal Academy Exhibition in London in 1782 where it shocked visitors as well as the critics. The painting draws on folklore, science and classical art to create a new kind of sexually-charged image.
And here’s a later version from 1802 with an even creepier and more menacing incubus:
Fuseli was fascinated with the darker side of human nature and this is probably the reason that many of his works focus on suppressed violence, fears people have which are illogical and often foolish and sexual perversity.