Their minds and bodies in the throes of a real condition called sleep paralysis.

When triggered, the symptoms are usually mild.

From tense muscles, to labored breathing.

But for some, the experience conjures hallucinations that make nightmares come alive.

Here are some of their stories.

Before I learned to cope with it, I've seen quite a few awful things.

Horror films don't really...they don't really do anything for me anymore because what I've seen is more terrifying.

The earliest I can remember is seeing a figure that looked like my mother sitting on my bed.

Her face is then morphing into some kind of demon.

Another time, a little girl was in the corner just staring at me.

Then without notice, she shrieks and runs up and grabs me by the neck.

You try to call for help but your voice, it doesn't work and your body won't respond.

You just feel helpless.

On one particular night, I felt like someone was looking at me from the foot of my bed.

I knew that nothing was there but I was afraid to open my eyes.

When I did, I saw a woman's head looking straight back at me.

She didn't have a body or even a neck.

Just her head.

I still remember the smirk she had on her face.

I closed my eyes immediately and I was unable to move.

When I felt it was safe, I opened my eyes again.

She was still there.

And she began to laugh at me.

I closed my eyes again, hoping she would disappear.

Then, I heard this scoff.

And she was gone.

So, I remember waking up and feeling a presence in the room.

And I see this woman in a black dress looming above the floor.

And she kept coming closer and closer to me.

I could feel my throat closing and I couldn't breathe.

As soon as she made it towards me she floated right in front of my face and started screaming.

I bolted out of my bed and I tried to wake up my parents.

Little did I know, I was still dreaming and I ended up back in my bed in another sleep paralysis experience.

It's something that's so wild and surreal that there's no logic to it.

So if you wake up one day paralyzed by horrific visions remember to stay calm.

And understand that your nightmares are only as real as you make them.