Most people have had the feeling they're being watched, or heard things go bump in the night.
Sometimes our minds and imaginations can run riot when we're in silent, dark bedrooms - our ears tuned in for any sound.
One man appears absolutely convinced he's being haunted by the ghost of a demonic baby and has thousands of people captivated by his storytelling.
Adam Ellis, from New York, began tweeting about the spooky goings on a few months ago, sharing his experiences of creepy dreams in which a devilish ghost baby with a dented head featured.
The story began on August 7, when Adam tweeted: "So, my apartment is currently being haunted by the ghost of a dead child and he's trying to kill me.
"He started appearing in dreams, but I think he's crossed over into the real world now."
"For a while he just stared at me, but then he got out of the chair and started shambling toward the bed," Adam writes.
"I couldn't move because I was paralyzed. (I have sleep paralysis fairly often. It sucks.)
"Right before he reached my bed, I woke up screaming.
"I had another dream a few nights later, where I was in a library and a girl came up to me and said, 'You've seen Dear David, haven't you?'"
The rest of Adam's Twitter feed provides a plethora of other creepy stories and videos of plants falling off shelves and rocking chairs moving of their own accord.
He says he moved to the apartment upstairs and thought he was free from the dreams or so-called "haunting".
But soon afterwards his cats, he says, would gather at the front door at midnight and look up at it, as if they were listening to something on the other side.
His latest tweets are the most terrifying
On November 7, Adam told the story of how the night before he had experienced another nightmare involving 'Dear David' staring at him from his bedroom chair.
He felt totally paralysed and couldn't move as 'David' left the chair and struggled across the bedroom towards him, murmuring under his breath as his eyes rolled back in his head.
Adam says in his dream he thought "If David is going to kill me, maybe I can at least get evidence on my phone," and started snapping pictures in the dark.
Scroll down for the lightened versions of the photographs
David climbed onto the bed and Adam woke with a start. It was broad daylight, the coast was clear and he was out of his bad dream.
But the next night, as he was looking for a photo on his phone, he says he noticed 'dozens of pitch black photos' in his camera roll from the previous night.
He shared three photos - all too dark to see anything - but insists you turn brightness up to see the photo which "made his heart drop".
Most Read
Adam keeps his followers up to date with the spooky goings-on, but he hasn't posted since that day.
Of course, it could all be part of an elaborate prank.
But with approximately 2,000 likes for every tweet, it seems he's got a rather captivated audience who can't wait to find out what happens next in his story.
You can follow Adam's spooky updates on his Twitter account here.