Date of Discovery

Linguistically speaking the etymology of the word Nightmare dates back to the 1300s, but the phenomenon has been under investigation as far back as the second century.

c. 1300, “an evil female spirit afflicting men (or horses) in their sleep with a feeling of suffocation,” compounded from night + mare (n.3) “goblin that causes nightmares, incubus.” The meaning shifted mid-16c. from the incubus to the suffocating sensation it causes. Sense of “any bad dream” is recorded by 1829; that of “very distressing experience” is from 1831. Cognate with Middle Dutch nachtmare, German Nachtmahr. An Old English word for it was niht-genga. – “Nightmare”


The Nightmare is a type of demon that is also known as a Night Terror, Night Hag, and Old Hag. Unlike the named demons that make up the commanding force of demonic entities, these lesser demons are known only by their function.

Physical Description

Although there isn’t a consistent description of the Nightmare, the various descriptions throughout the history of the demonic entity suggest that it can take a variety of forms. In most cases, the demon presents as an invisible entity, although there are reports of it being a dark shadowy figure or an inhuman and demonic shape. Most reports indicate that its breath can be heard as a low rasp, it possesses glowing red eyes, as well as a strong revolting odor that fills the room in its presence.


The best guess on where the Nightmare originated is second-century Greece when Galen of Pergamon first investigated the phenomenon.

Mythology and Lore

As can be assumed by the name, the Nightmare attacks mostly at night but is known to do so at any given time during the day or night. Within the paranormal community, the Nightmare is often confused with poltergeist activity, and in rare cases has been associated with vampire attacks. The Nightmare is also related to the Mara (also known as a succubus), another type of demon that attacks humans at night, with the ultimate goal of sexually assaulting them.

As a typically nocturnal influence, the nightmare strikes people when they sleep, often causing the individual to experience strange smells, sounds, and images, then causes suffocation and a phenomenon known by the scientific community as sleep paralysis. Other characteristics are varied from case to case but remain a consistent variable when taking into consideration all of the reported attacks. These cases involve the individual waking from a deep sleep unexpectedly to the sensation of an unseen entity sitting upon their chest—the individual’s attempts to move, struggle, speak or scream are futile, which is understandably the most frightening aspect of the attack. It seems the Nightmare’s purpose is not to kill, as the attack ends just before the individual passes out. The victim typically recalls all details of the alleged attack the next day and demonstrates a prolonged sense of mental, emotional, and physical fatigue.

In some reported cases of a Nightmare attack, victims are awakened to audible footsteps approaching them as they lay in bed, while there is no figure to attach the footsteps to, they immediately feel the effect of being paralyzed, likely due to extreme fear.

Nearly 15% of the adult population worldwide has reported having at least one attack from a Nightmare within their life, according to modern research. Documented in second-century Greece, physician Galen of Pergamon analyzed several patients who reported having nightmares but attributed the phenomenon with indigestion. While it’s still often proposed as an explanation for individuals reporting such cases to their doctors there are a couple of other theories that have been developed since—commonly, sleep disorders such as narcolepsy, as well as the rare case of repressed sexual tensions. Suffice it to say, these explanations may be accurate for some of the cases, but it does not satisfy them all.

During the Middle Ages, when circumstances such as this were being investigated, it was normal for the explanation to be something supernatural, such as witchcraft to be the cause. In fact, the names, “Night Hag,” as well as, “Old Hag,” refer to an older term for witches, “hag.” Witches were believed to come into a victim’s house at night and then, “ride,” a person’s chest at night, causing the victim to feel as if they were being suffocated, then exhausted the next day. This is actually where the term, “hagridden,” was born, to indicate a feeling of being run down, or exhausted. It was also common for individuals to accuse witches of attacking them magically, by cursing them and sending a demon to attack them. It was a common belief that a religious object held close to the body, or an amulet worn around the neck would ward off any potential Old Hag encounters.

Modern Pop-Culture References


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