In Western medieval legend, a succubus (plural succubi or succubuses) or succuba (plural succubae) is a demon who takes the form of a beautiful human female to seduce men (especially monks) in dreams to have sexual intercourse. They draw energy from the men to sustain themselves, often until the point of exhaustion or death of the victim. From mythology and fantasy, Lilith and the Lilin (Jewish) and Lilitu (Sumerian) are, in redactive Christian fables (folktales not part of official Christian theology), considered succubi.
According to the Malleus Maleficarum, or "Witches' Hammer", succubi would collect semen from the men they slept with, which incubi would then use to impregnate women. Children so begotten were supposed to be more susceptible to the influence of demons.
In some beliefs the succubi would metamorphose into the Incubus with its newly collected semen ready to impregnate their victims. This was to account for the fact that demons could not reproduce naturallyclarify], however the incubus could impregnate women.clarify]
From the 16th century, the carving of a succubus on the outside of an inn indicated that the establishment also operated as a brothel.