may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. The talk page may contain suggestions. (August 2009) Incubus, 1870 An incubus (from the Latin, incubus, or "nightmare"; plural incubi) is a demon in male form who, according to a number of mythological and legendary traditions, lies upon sleepers, especially women, in order to have sex with them. Its female counterpart is the succubus. An incubus may pursue sexual relations with a woman in order to father a child, as in the legend of Merlin. Religious tradition holds that repeated intercourse with an incubus or succubus may result in the deterioration of health, or even death..