 When you first hear a sleep paralysis story, it can be all too easy to dismiss it as something fake or all in the teller's mind. You wake up, you know you're in danger, an intruder is after you, the water is rising above your head, an evil creature is sitting on your chest and crushing the air out of your lungs. You need to escape, but you can't move, you can't even scream or call for help. Could it have been real? The answer is yes. I'm Darren Marlar and this is Weird But True, a companion to Weird Darkness. Sleep paralysis is real and it happens for a very good reason. It would be extremely dangerous if we could act out our dreams in real life. Just as comedian Mike Bebelia, he has a rare sleep disorder in which he is not paralyzed while dreaming. He made a very funny, very scary movie about his experience called Sleep Walk With Me. It tells the true story of the night he jumped through a second floor motel window and ran bleeding across the lawn because he was dreaming about being chased. Scary as it would be to wake up bleeding in our underwear on a motel lawn, it's also pretty scary to wake up paralyzed in the middle of a nightmare. Sleep paralysis is common enough that most of us have experienced it at least once. Some people experience it frequently. An irregular sleep pattern and stress might be triggers. Sleep paralysis may have been the inspiration for many of these scary images and art of demons sitting on the chests of helpless people. Some researchers believe sleep paralysis may even be the source of stories of alien abductions. A quick search of sleep paralysis stories turns up some truly scary ones. For example, a little creature is chewing something on the floor. In an instant, it's next to my head and whispers remember me. Another person said, an evil old lady over my head whispers darling. Something is banging and scraping on the locked bedroom door which starts to open. Something evil is pulling me into a deep and dangerous place. I can't cry for help or even move a finger. I wake and a little girl in the corner of the bedroom is staring at me. Then she shrieks and runs to the bed and starts choking me. A giant beetle is getting ready to eat my body. These are just some of the stories of sleep paralysis that people have told. Sleep researchers believe we dream during the phase of sleep called REM rapid eye movement. It is believed that when we enter REM sleep the brain cuts off the connection to the muscles so we can run around in our dreams without risk of leaping out of bed. But when that paralysis lingers for a few minutes into wakefulness after a scary dream it can be a very unpleasant experience. Those who experience sleep paralysis often report feeling like a devil is crouching on their chest or that they feel as though they have been possessed by another entity. The real explanation is a bit less paranormal but it is certainly terrifying nonetheless. Knowing why your body has stopped being able to move won't necessarily stop your panic when it occurs.