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Published on: 2/18/2026
Seeing a dark shadow figure in your room at night is usually a sleep-related hallucination from sleep paralysis or REM transitions, amplified by low light pareidolia, stress, and sleep deprivation; it is common and typically benign. There are several factors to consider; seek care if episodes occur when fully awake, are frequent or worsening, involve acting out dreams or injuries, new neurological symptoms, or possible medication or substance effects, since conditions like REM Sleep Behavior Disorder may be involved. See below for practical steps to reduce episodes, key red flags, and a symptom check link to guide next steps with a clinician.
Many people have experienced it at least once: you wake up in the night and see what looks like a dark figure standing in the corner of your room. Your heart races. You blink—and it's gone.
If you've had hallucinations seeing a "shadow person" standing in the corner, you're not alone. This experience is far more common than most people realize. While it can feel frightening, there are well-understood neurological and sleep-related explanations behind it.
Let's break down what's really happening, when it may signal a medical issue, and what you should do next.
Your brain is a prediction machine. It constantly fills in gaps based on limited information. In low light, especially at night, your visual system struggles to interpret shapes accurately. When combined with sleep-related brain activity, this can produce vivid, realistic hallucinations.
Several mechanisms may explain hallucinations seeing a "shadow person" standing in the corner:
One of the most common causes is sleep paralysis.
Sleep paralysis happens when:
REM (Rapid Eye Movement) sleep is the stage where most dreaming occurs. During REM, your brain temporarily shuts off muscle movement to prevent you from acting out dreams.
If you wake up before this paralysis ends, you may:
These figures are often described as:
Research shows that up to 30–40% of people experience sleep paralysis at least once in their lifetime.
These are hallucinations that occur:
During these transitions, your brain blends dream imagery with waking awareness. You may see:
Because your brain's threat-detection system is highly active at night, these figures often appear threatening—even though they are not real.
Humans evolved to detect danger quickly. In dim lighting, your brain prioritizes identifying potential threats over accuracy.
In darkness:
This phenomenon is called pareidolia—seeing meaningful images in random patterns (like faces in clouds). In low light, a coat rack or curtain can briefly look like a person.
When combined with fatigue or stress, the experience can feel extremely real.
In some cases, recurring nighttime hallucinations may be linked to sleep disorders.
One condition to be aware of is Rapid Eye Movement (REM) Sleep Behavior Disorder (RBD).
RBD occurs when:
If you experience:
You should take Ubie's free AI-powered Rapid Eye Movement (REM) Sleep Behavior Disorder symptom checker to help identify whether your symptoms align with this condition and determine if you need professional evaluation.
RBD can sometimes be associated with neurological conditions, so early evaluation is important.
This is one of the biggest fears people have.
Occasional hallucinations seeing a "shadow person" standing in the corner during sleep transitions are not automatically a sign of schizophrenia or psychosis.
Here's how sleep-related hallucinations differ from psychiatric hallucinations:
If hallucinations happen during the day, involve voices, or interfere with daily life, that requires prompt medical evaluation.
While sleep phenomena are most common, other medical factors can contribute:
Lack of sleep can cause:
Stress increases nighttime arousal and hypervigilance, making the brain more likely to misinterpret shadows.
Some medications (especially those affecting dopamine or serotonin) may cause visual hallucinations.
Alcohol withdrawal, stimulant use, or certain drugs can trigger shadow-like hallucinations.
Rarely, persistent visual hallucinations may be linked to:
If hallucinations are new, frequent, or worsening—especially in older adults—medical evaluation is essential.
People often ask: If it's just my brain, why does it feel so real?
The answer lies in REM sleep.
During REM:
When dream content spills into wakefulness, it feels indistinguishable from reality for a few seconds.
Your brain is not malfunctioning—it's just caught between sleep and wake states.
You should speak to a doctor promptly if:
Any symptom that could signal a serious neurological or psychiatric condition deserves professional evaluation.
If your experiences are related to sleep, these steps often help:
If symptoms persist, a sleep study may be recommended.
Experiencing hallucinations seeing a "shadow person" standing in the corner can feel terrifying—but in most cases, the explanation is rooted in normal sleep physiology.
The most common causes include:
These experiences are common, especially during periods of stress or poor sleep.
However, recurring, worsening, or daytime hallucinations should never be ignored. Certain sleep disorders—like REM Sleep Behavior Disorder—may require medical attention. If your symptoms match that pattern, Ubie's free AI-powered Rapid Eye Movement (REM) Sleep Behavior Disorder symptom checker can help you understand your symptoms and determine whether you should seek professional care.
Most importantly, if you experience anything that feels severe, persistent, or potentially life-threatening, speak to a doctor immediately. Early evaluation can rule out serious causes and provide peace of mind.
You are not "losing your mind." In most cases, your brain is simply misfiring during a delicate transition between sleep and wakefulness. Understanding the science behind it often removes much of the fear.
And when in doubt, get checked. Your health—and your sleep—are worth it.
(References)
* Sasaki, T., Matsumura, A., Yoshizaki, T., Iwanami, J., Nakagawa, A., & Ogiya, H. (2019). Seeing things that are not there: Hypnagogic and hypnopompic hallucinations. *Sleep Medicine*, 54, 1-7. [PMID: 30612143].
* Liu, J., Li, J., Fang, F., & Gou, L. (2014). Face Pareidolia: A Neuropsychological and Neuroimaging Perspective. *Frontiers in Human Neuroscience*, 8, 995. [PMID: 25520625].
* Komatsu, H., & Nishida, S. (2014). The neural mechanisms of filling-in for visual awareness. *Vision Research*, 104, 39-50. [PMID: 24054625].
* Alderson, R. M., Teeple, R. C., Caplan, J. P., & Weinberger, D. R. (2018). Mechanisms of Visual Hallucinations. *Current Opinion in Neurology*, 31(6), 725-731. [PMID: 28732890].
* Spratling, M. W. (2013). Predictive coding in the visual cortex: the neural basis of perceptual inference. *Philosophical Transactions of the Royal Society B: Biological Sciences*, 368(1620), 20130055. [PMID: 23880461].
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