Monster of the Week: Incubi and Succubi

Know your demon lover.. IgorIgorevich/iStock

Last week we looked at the mara or nightmare, a chest-crushing entity that preys on the breath of troubled sleepers. While we discussed several varieties of mara, we didn't explore the sexual world of incubi and succubi.

The incubus: Translated as "that which lies upon," incubi carry out the same basic torment tactics as your common nightmare, only with more grinding. Not content to merely crush its victim, the incubus also pursues sexual relations. Most commentators describe the creature as male, but according to folk historian Carol Rose, the shape-shifter can take on both male and female forms, though it preys exclusively on the ladies. This is interesting as it shows how deep homophobia ran in medieval culture. As Walter Stephens pointed out in "Demon Lovers," witchcraft theorists of the day concocted all sorts of bawdy demon-on-human scenarios for accused witches of both genders, yet balked at the notion of male demons engaging in gay sex.

The succubus: For the most part, we can regard this species as a close relative to the incubus rather than a gender counterpart. While the incubus is "that which lies upon," the succubus draws its name from the latin sub (under) and cubare (to lie down). So its tactic is somewhat altered from that of a typical nightmare. It abandons the crushing tactic of its cousins and cranks up the sexuality with a submissive flare. It exclusively targets male victims and may take the form of a known, unknown or invisible female - or even a withered hag or crone.

Sperm Thieves, Duck Feet and a Crisis of Faith

In the realm of monsters, it's all about ensnaring new satanic servants and producing satanic children via artificial insemination.

According to 15th century Bishop Alonso Tostado, a succubus may lay with a man in order to collect his semen and then morph into an incubus in order to fertilize a female victim with the ill-gotten sperm.

In the realm of men, however, most of this boils down to a frenzied, murderous attempt to prove the existence of the afterlife via the coerced confessions of tortured women. But that's a topic for another post.

As far as the shape-shifting goes, remember that incubi and sucubi are imperfect mimics. Whether taking the form of a victim's husband or a sexy young drifter that looks like Ryan Gosling, the demon never gets the feet right. So make sure your midnight lover takes his or her socks off. If they have duck feet, then you know you've been duped.

Nature is full of imperfect mimicry, but witchcraft theorists generally attributed this foot flaw to a little divine intervention. After all, a just God would surely provide his faithful servants with an out. If you keep on making love after you spot the monster feet, then well... this one's on you.

Monster of the Week is a - you guessed it - regular look at the denizens is of our monster-haunted world. Sometimes we'll focus on the cultural aspects, but mostly we'll look at the possible science behind a creature of myth, movie or legend. Be sure to explore the Monster Gallery as well as the Monster Science video series.

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.