An incubus is a demon in male form in folklore that seeks to have sexual intercourse with sleeping women; the corresponding spirit in female form is called a succubus. Parallels exist in many cultures.

A succubus is a demon or supernatural entity in folklore, in female form, that appears in dreams to seduce men, usually through sexual activity. According to religious tradition, a succubus needs semen to survive; repeated sexual activity with a succubus will result in a bond being formed between the succubus and the man; and a succubus will drain or harm the man with whom she is having intercourse. In modern representations, a succubus is often depicted as a beautiful seductress or enchantress, rather than as demonic or frightening. The male counterpart to the succubus is the incubus.