geeky guide to halloween

Via annedela at

It’s likely that Halloween can be explained by two tiny almond-sized regions deep in your brain. By researching neuropsychology and history, a primal code appears that describes 5-6 specific stories that terrify our brain senseless. Once you know them, you can design a truly scary Halloween costume or outline many horror books and screenplays.

the floating eyeball that wouldn’t go away

Evil eyeball via

When I was eight, I awoke to a bloodshot eyeball the size of a softball glaring down on me. I closed and opened my eyes — expecting it to be gone — but it wouldn’t go away and terrorized the space above my bed for half an hour.

The experience was petrifying. When my politely concerned parents suggested that the eyeball was a dream or a bird, I was aghast, “Dang it – now I have to risk my life catching that blasted, deathly eyeball before you’ll believe me?!”

The mystery unraveled in college when I learned about the brain’s amygdala. I went on a research deep-dive and realized, “Wait a second — this is the secret to a great Halloween costume or horror film!”

the culprit amygdala

Courtesy of Creative Commons

The amygdala, a small low-level region of the brain a few inches behind each eye, seems perfectly wired for Halloween. It is responsible for the fight or flight response, keeping a library of what is scary in the world, detecting fearful facial expressions, and waking its dreamer when something goes bump in the night.

Hyperactive amygdalas (generally from stress, sickness, food reactions, poor sleep habits, or genetics) can trigger hallucinations and paralysis while we pass in and out of sleep. The experience isn’t always negative but when it is, it becomes a “night terror.” This is very different from a nightmare. Only 6% of the general population is believed to ever experience the prerequisite sleep paralysis [1] and a full-blown hallucinatory “night terror” (also referred to as pavor nocturnus, hypnagogia, or hypnopompia) is far rarer.

But what’s astounding is that most night terror hallucinations, spanning nearly all cultures and over thousands of years, are remarkably similar!

This suggests that some experiences are universally scary. Interviewing your amygdala is impossible and designing a psychological experiment to scare subjects is unethical. However, night terror accounts provide a convenient glimpse into that hidden psyche.

how a night terror happens

The Nightmare by Henry Fuseli (1741–1825)

A few things must misfire for a night terror to occur. First, the amygdala must be in deep REM sleep where it has the most vivid, fanciful dream activity. But before the amygdala runs and flies into wild REM sleep stories, it warns the brainstem to immobilize the body so that the dreamer remains safe and still instead of thrashing about in their sleep.

However, occasionally the amygdala and motor shut-off signals fall out of sync before or after REM sleep. If our mind becomes conscious before the body, we can wake up paralyzed or numb. Sudden-onset paralysis is already frightening but being frozen while a fear-obsessed amygdala is in overdrive can turn terrifying!

Once frozen but conscious, the amygdala hallucinates within the bedroom scene. Suddenly ghostly apparitions appear to crawl out of closets and emerge from shadows while the dreamer remains helpless. The dreamer can even feel their intruder’s cold touch or painful pinches. Night terrors are frequently accompanied by shortness of breath and chest compressions so strong that one account describes them as “a ton of rocks upon my chest.” However, dreamers are unaware of these mechanics and attribute the sensation to the intruder crawling upon their body and riding them to near suffocation. The experience is so real that it is often hard to convince the victim that the terror didn’t actually happen.

Though night terrors vary, all night terrors exploit one fear — an intense and overpowering anxiety that something is “out to get you.” Our amygdala’s worst fear is not public speaking or the dentist but being chased or pursued with the intent to kill.

“Ichabod Crane, Respectfully Dedicated to Washington Irving.” William J. Wilgus (1819 – 1853)
The headless horseman chasing Ichabod Crane

the 6 night terrors

Here are sure-fire ways to scare the beejezus out of your Halloween buddies. Academic research and historical accounts typically identify the old hag, incubus/succubus, and vestibular motor sensations (dizziness, vibrations). Outside of research, contemporary accounts also include alien abductions and vermin.

1. The Old Hag

Snow White, Frankenstein, Wizard of Oz, Tales from the Crypt, and Night of the Living Dead

Example: Your ghoulish deceased grandmother appears in your bedroom, slowly approaches, crawls upon your chest, and proceeds to suffocate you with her weight.

The old hag night terror refers to an old or deceased woman who appears at night and crawls upon the dreamer’s chest to choke, assault, or suffocate them. Though it’s called an “old hag,” a ghoulish male equivalent exists too. Witches, mummies, and zombies are an embodiment of this terror. With skeletons, the dreamer sometimes awakens to find the skeleton sleeping beside them. And more recently, online forums are filled with accounts of creepy children who crawl into the room to attack the dreamer.

Interestingly, Mary Shelley supposedly developed the vision for Frankenstein based upon a “dream vision” and it’s worth nothing that Dorothy’s interactions with the Wicked Witch of the West occur while she is sleeping. On Halloween, the old hag is represented by the classic pointy hat witch costume.

2. Evil Species

Engraving from Charles Nodier’s “Tales” (probably inspired by Henry Fuseli) (1846), King Kong, Gremlins, Terminator, Aliens,
and Forbidden Planet (1956)

Example: A giant expressionist monster with glowing eyes enters your room through a crack in the window, immobilizes you telepathically, and proceeds to suck the life out of you with its super powers.

Sometimes the menacing presence is not entirely human but a demon, gremlin, monster, or animal. In research, these are typically classified as types of old hag hallucinations and the overall intent is the same — to physically assault the dreamer. However, there’s a subtle distinction that I think makes it worthy of it’s own category. Unlike deceased human corpses, the amygdala appears to invent a threatening superior species. In history, this has been a stronger demon, a monster laden with teeth, or a creature with supernatural powers like a werewolf at full moon. Today, there are fewer accounts of these demons. However, alien abduction stories are rampant and many researchers believe that these are modern night terrors exposing a deep fear of a technologically superior species.

3. Femme Fatale & Ladykiller

Medieval woodcut of lustful Pan from Darrah Anderson with 3:AM Magazine, Snow White (1937), La Chiesa, Dracula (1931),
Phantom of the Opera, Lilith by John Collier (1892), and Basic Instinct

Example: The devil appears in your bedroom and wants to impregnate you with his spawn.

Though it’s controversial to mention, history is riddled with accounts of the incubus (male) and succubus (female) — evil lustful spirits that use their sexual wiles to seduce and assault their dreamers. This is the classic tale behind Rosemary’s Baby.

In the Medieval period, these reports were so pervasive that if a woman unexpectedly became pregnant while her husband was away, the demonic incubus was suspected before infidelity or rape. The male form is controversial and many suspect that historical accounts of incubi have been scape-goats for history’s sexual offenders. However, Bram Stoker’s Dracula, Rosemary’s Baby, and the Phantom of the Opera are almost certainly of incubus folklore.

The female equivalent, a femme fatale, generally takes the shape of a demonic angel (she-devil) with pronounced sexual features like large breasts, long hair, and sometimes wings. In some cases, the female form attacks the children of the dreamer. Most cultures have a Lilith/Eve temptress within their folklore – some dating back thousands of years. It’s not at all far-fetched to suggest that religion may have taken a cue from a hyperactive amygdala!

4. Vibrations & Noise

Alice in Wonderland (1951), Vertigo (1958), Exorcist (1973), haunted house via

Example: You wake up to paralysis. You strain to open your eyes or sit up in bed but even the smallest movement is impossible. You’re trapped in your head’s darkness growing dizzier by the second. A buzzing noise joins your darkness and gets louder and louder, closer and closer. You try screaming for help but you are still paralyzed. The buzzing noise is overwhelming and all-consuming. The darkness has become a whirlpool and the buzzing is so loud your head is shaking. At any moment, you’re afraid that your head might explode.

Night terrors do not always include a living intruder. Sometimes dreamers find themselves shaking uncontrollably, falling, dizzy, or just experience the world off-kilter — like a whirlpool appearing within the room, Alice falling down the rabbit hole, the heartbeat beneath the floorboards in Edgar Allen Poe’s Tell-Tale Heart, or violent shaking that cracks bedroom walls.

Some night terror victims have an experience more akin to a noise. The “exploding head syndrome” refers to a noise trapped in the dreamer’s head that spins around getting louder and louder until the dreamer fears their head will explode.

Other noises include explosive door slams, gunshots, or explosions that immediately wake the dreamer. Or, the dreamer is paralyzed but hears far-away noises like screams, laughter, ringing, or wind getting louder and louder foreshadowing something ominous. This explains haunted house noises and perhaps why shaky hand-held camera effects elicit scary spine tingles.

As an aside, it might not be a Halloween costume, but if you’re going to write a horror film, the vibration category is my bet. Pop culture has desensitized us to vampires and zombies but the “exploding head syndrome” is rife with opportunities.

5. Vermin

Silence of the Lambs (1991), The Invasion of the Vampires (1963), rats in ceiling via,
Indiana Jones and the Last Crusade (1989), The Birds (1963)

Example: The wallpaper shifts, squirms, and starts crawling with hundreds of rats. The rats crawl from the walls to the ceiling above your bed and then fall into your bedsheets. They keep coming. Soon you are swimming in rats that want to overtake you.

Creepy crawly apparitions vary by culture — one culture’s cockroach is another culture’s chameleon. However, spiders, bats, lizards, cockroaches, snakes, and rats appear frequently on English-speaking forums. If the beady-eyed intruder is alone, it is typically over-sized, flying, and potentially baring teeth. Swarms of critters tend to crawl up ceilings and drop on the bedsheets of their dreamer.

After reading many vermin night terror accounts, I suspect that patterned wallpaper, curtains, and carpets provide the perfect canvas for the amygdala to go nuts. A significant number of vermin stories start with the wallpaper shifting into squirming snakes and spiders. Personally, I love fantastic wallpaper in horror films (like The Shining’s hotel) but I’d be in favor of banning wall and floor patterns in hospitals. Sickness and fever is a predictor for night terrors and the hospital is a place where I definitely want my amygdala shielded!

6. Fear of the Unknown

Repulsion (1965), Cheshire Cat from Alice in Wonderland (2010), The Son of Man by René Magritte (1964), evil eyeball via, monster under bed via

Example: You wake up with a sense of overwhelming dread. You know something is in the room. It is very cold and you feel more alone than you ever have before. Whatever it is has already taken everyone else in the house and is now coming after you. You are petrified with fear. Each second the presence doesn’t reveal itself just leaves you in greater suspense.

Many visual hallucinations are incomplete or semi-transparent versions of themes 1-5: teethy jaws, ghosts, shadowy figures, faceless spirits, floating heads, arms emerging from walls or closets, and countless variations of evil eye hallucinations — floating eyeballs, red glowing eyes, or white eyes with no iris. In some cases, there is no intruder at all but just an unbearable presence that is perhaps worse than if the hallucination took full shape. This could be the monster that lives under the bed or the still shadow who keeps the dreamer in terror-filled suspense.

Within Halloween, the jack-o-lantern approximates a dismembered floating head and it’s easy to see why the ghost costume is so popular. However, if you’re looking for a great Halloween costume, the faceless shadowy figure wearing a brimmed hat and business suit (or trenchcoat) is one of today’s most common night terror hallucinations.


If you’re thinking, “Now I have to fall asleep after reading about the old hag. Thanks a lot Elaine.” I have good news. The more you know about night terrors the less likely you are to have them. And in fact, this may be the reason that Halloween exists at all – the more we reconcile our worst fears the less likely our amygdala goes ballistic when we’re deep asleep.

However, if you freeze with sleep paralysis tonight, many reoccurring night terror victims say that thinking positive thoughts and willing yourself to spin out of bed from your side instead of sitting straight up will break the paralyzing spell.

Happy Halloween!

Via annedela at

5 responses to “geeky guide to halloween”

  1. Spooky! Nice article (I’m so glad I’m reading this in the middle of the day).

    Another phenomenon worth exploring is “Infrasound” which explains ghosts and feelings of terror when people are wide awake…

    • Khuong, that’s awesome! In addition to wallpaper, we can add anything that generates 19 Hz frequencies to the list of things to ban in hospitals too. Thanks for mentioning!

  2. Thanks dmtr. Deviatart is a great place to find contemporary evil demons – thanks for pointing that out. And, I’m very glad I’ve never seen a cacodemon!

Leave a Reply