An incubus (nominal form constructed from the Latin verb, incubo, incubare, or "to lie upon") 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 sexual intercourse with them ,, 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