Sleep Science

AI Brings ‘Sleep Demons’ to Life

An image of Autumn Wiberg-Roberts
20 Oct 20226 min read

Throughout history, people across the globe have reported incidents of waking in the night, unable to move, with feelings that a presence has trapped them in their beds. Many likened the experience to a demon or dark creature sitting on their chest, holding down their body.

These encounters have slowly worked their way into culture as folkloric tales of ‘sleep demons’ paralysing their victims to capture their souls.

Modern scholars speculate that many of these incidents are actually reports of a condition known as sleep paralysis, where sufferers feel their brain has woken up before their body, leaving them unable to move or speak for a short period of time. 

The idea of a ‘sleep paralysis demon’ is still associated with the condition today. Cultures around the world have created many different interpretations of this phenomena. One of the most common representations is the ‘night hag’, a supernatural malevolent being that stands on a person’s chest as they sleep.

Elsewhere, sleep paralysis demons are believed to be the ghosts of deceased relatives or even aliens! 

Each sleep paralysis experience is unique, but are there similarities in many of the ‘demons’ we see? During this Halloween period, Mattress Online investigates…

The most common sleep demon representations

Those who have experienced this phenomena invariably turn to the internet for answers. There are, in fact, over 500 Google searches every month for the term ‘sleep paralysis demon’.

We’ve analysed those monthly searches to find out which representations of sleep demons are most common. Below, you’ll find a list of the 10 most common sleep paralysis demons, based on number of Google searches:

Top 10 most Googled sleep paralysis demons

  1. Old hag
  2. Man
  3. Hat man
  4. Shadows
  5. Electrical buzzing
  6. Hearing voices/screams
  7. Witch
  8. Spiders
  9. Electric shock feeling
  10. Demon on chest

As part of our Halloween investigation, we fed some of this data into an artificial intelligence programme to generate images of some of the most commonly experienced sleep demons. Below are some of our favourites. 

But beware - this is not for the faint of heart!

Old hag sleep demon

Old Hag sleep paralysis demon

According to our search data, the old hag is the most common sleep demon. This could be because of the popular night hag folklore that exists in many cultures around the world.

Hat man sleep demon

Hat man sleep paralysis demon

Interestingly, a man wearing a hat is another common representation. Although he may seem fairly ordinary, the hat casts an eerie shadow across the creature’s face. Obscuring the view of his face creates a sense of unease, making this figure certainly unsettling.

Shadow sleep demon

Shadow sleep paralysis demon

Even when awake, shadows can create a sense of unease and a tension, suggesting that there’s somebody in a room who shouldn’t be. Perhaps this anxiety is one of the reasons why shadow sleep demons are so common.

Screaming sleep demon

Screaming sleep paralysis demon

Hearing voices or screams is another common experience associated with the condition, according to our research. It isn’t unusual for some sufferers to hear noises including buzzing, hissing or humming.

Witch sleep demon

Witch sleep paralysis demon

As one of our top ten sleep demons, the witch demon is perhaps the one we most commonly associate with horror movie imagery.

Dream interpreter Inbaal Honigman explains the most common themes in sleep paralysis experiences: “Most sleep paralysis nightmares fall under three main categories. 

“Primarily the dreamer perceives to be viewing a humanoid shadow, such as a hat-man, old hag or monster, believing someone is in the room with them. 

“A second widespread nightmare is the inability to scream, someone compressing their chest, or even struggling to breathe. And the third one is hearing something terrifying, like a buzzing or a scream.”

Sufferers discover hidden meanings behind real-life sleep paralysis experiences

We spoke to three different people about their real-life sleep paralysis experiences and asked Inbaal to reveal the associated hidden meanings:

Lauren’s experience of the smiling man sleep demon

Marketing Manager Lauren, 30, explains: “I couldn’t move but could see this man leering above me with a huge smile across his face. I used to have nightmares about a man stabbing me, it was always the same man. But when I woke up, I couldn’t move, and couldn’t scream.”

Unpacking Lauren’s experience, Inbaal offers: “Dreaming of being stabbed is linked with fear of betrayal or deceit. Stabbing is quick and quiet, it's not dramatic like a gunshot. So in a dream, it symbolises an underhand action, dishonest and subtle. 

“That it was the same figure leering and smiling strengthens this explanation – a friendly face upfront, a violent hand below. This experience demonstrates anxiety and an inability to trust those around them.”

Brian’s experience of a shadowy sleep demon

Graphic Designer Brian, 30, tells us: “I have woken up a few times not being able to move anything except my head. I tried raising my voice to wake myself up but no words came out – just noise. 

“There have been a couple of different sleep demons. Once, it looked like the girl from The Ring. A few other times it’s been like a tall shadowy figure in the corner of the room.”

Inbaal adds: “A humanoid shadowy figure is one of the most common anxiety dreams reported by many people across all cultures, whether in a state of sleep paralysis or not. It represents the shadow aspect of the dreamer themselves, the parts of their personality that they're ashamed of, unhappy about or would like to change.

“It can be perceived as a haunting, but it is a representation of all of the person's darkest emotions that they'd like to keep in the shadows.”

Sarah’s experience of a spider sleep demon

PR Executive Sarah, 28, comments: “I have it if I ever sleep on my back. I usually see loads of spiders above me or on my face and I can’t move or escape. A couple of times I’ve been sure I’ve felt someone sit down on the end of my bed too.”

Inbaal explains: “Anxiety dreams about spiders are quite common – seeing them scuttling out of the shadows shows a fear of the unknown, of what is hidden between the seen and the unseen. 

“The feeling of the bed moving is quite unique to sufferers of sleep paralysis. As the state of paralysis starts to loosen its grip on the dreamer, the uncertain physical changes in the body could make it seem as if the bed is moving.”

All of Inbaal’s interpretations of these three very different sleep paralysis experiences come down to one thing: anxiety. Interestingly, anxiety is often cited as a trigger for sleep paralysis.

Can watching horror movies increase your chances of experiencing sleep paralysis?

Whether it’s a Halloween movie marathon or you simply love watching the latest horror blockbusters, could watching scary movies before bed make sleep paralysis more likely? 

According to Inbaal, it could be true crime documentaries that have the most impact: “Halloween and horror movie imagery has become more and more commonplace and less jarring to the average person, and so they don’t necessarily cause any more undue anxiety during the Halloween period than the rest of the year. 

“Arguably, the recent overconsumption of true-crime content by viewers presents more of a risk, as the perception of violent criminals hiding in plain sight in our midst, could cause a much more heightened sense of anxiety than a trick-or-treating child in a plastic mask."

If you haven’t been scared completely silly just yet, why not take a look at our run-down of the most nightmare-inducing horror movies?


We determined the most common sleep paralysis demon using the average number of monthly Google searches for different sleep demons using data from Ahrefs.

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