Incubus: a famous type of demon known for engaging in sexual relations with women, and even impregnate them with half-human offspring known as cambions. Mentions of this demon go back as far as 2400 BC in the Sumerian King List. They sit on top of women's chest as they sleep before they seduce or assault them. Many reports of incubi are explained by the phenomenon of sleep paralysis, which causes the feeling on weight on the chest, and a half-dream state, causing the hypnagogic hallucination of a demon. While they normally choose female victims, there are reports of bisexual incubi. They are said to have unnaturally large and cold penises. art: John Henry Fuseli – The Nightmare, 1781. ⠀