Here Aquinas contradicted Augustine's biblical interpretation of Genesis 6:4 in which he attempted to prove that jinn begot children of mortal women 'The sons of God came in unto the daughters of men, and they bare children to them'. Aquinas further asserted that a demon could use semen lost during a wet dream so a man could be at one and the same time a virgin and a father. Also, aiding in this theory was the idea that demons were able to change their sex at will. Thomas Aquinas insisted that demons were sterile therefore the only way the incubus could impregnate a woman was by receiving the semen from a succubus who had received from a man.

In some legends, incubi and succubi were said not to be different genders of the same demonic species but the same demon able to change their sex the idea being that a succubus would be able to sleep with a man and collect his semen, and then transform into an incubus and use that seed on women. Guazzo described the incubus in his 'compendium Maleficarum (1608)Īs the incubus can assume either a male of a female shape sometimes he appears as a full-grown man, sometimes as a satyr and if it is a woman who has been received as a witch, he generally assumes the form of a rank goat. In modern psychological usage, the term has been applied to the type of nightmare that gives one the feeling of a heavy weight or oppression on the chest and stomach. The word incubo translates into 'I lie on top'. The word is derived from the Latin preposition in, which in this case means on top of, and cubo, which is Latin for 'I lie'.

Incubus band cartoon