incubus (ĭngˈkyŏbəs) [key], lascivious male demon said to possess mortal women as they sleep and to be responsible for the birth of demons, witches, and deformed children. According to one legend the incubus and his female counterpart, the succubus, were fallen angels. The belief in these demons was especially prevalent in the Middle Ages, and stories of assaults by incubi were not uncommon. There are similar spirits in many cultures. In current usage, incubus means a person or thing that oppresses, such as a nightmare.
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