Sleep paralysis demons have become a key figure in meme culture, but they aren't so funny for those who experience them.

Maybe you’ve seen the meme: “This is my sleep paralysis demon: [insert photo].” The viral idea builds on a very real condition in which a person is conscious but unable to move. In some ...

The Roblox game Frogge is a horror game created by Sleep Paralysis Demons. If you are looking for the latest 'Frogge' codes, then you have come to the right place.

Unfortunately for me, I had my very own sleep paralysis demon. The only problem (well, besides the bone-chilling looming presence in my bedroom)? I had no idea what it was until seven years later.

The sleep demon is actually a hallucination linked to sleep paralysis, which occurs when a person is jolted awake in the middle of the rapid eye movement (REM) phase of sleep associated with dreaming.

The hallucinations experienced during sleep paralysis are either hypnagogic hallucinations, which occur when a person is falling asleep, or hypnopompic hallucinations, which happen when waking up.

The Nightmare by John Henry Fuseli depicts sleep paralysis, which some report feels like a demon sitting on your chest or a presence in your bedroom. Universal History Archive/Getty Images ...

Graham Falk speaks to sufferers of the terrifying phenomenon known as sleep paralysis, the disorder which can leave sufferers seeing nightmarish demonic figures in their bedroom.