In the new documentary “Your Worst Nightmare,” Amy in Mount Vernon, a young woman with long black hair tucked behind her ears, tells the camera that it felt like her lips were being sewn shut. Her body went numb.

“I felt like he was coming.”

“He” was an unseen entity that pushed down on her chest and made her afraid to go to sleep. Others talk about the Black Shadow, a menacing silhouette, and an Old Hag who creeps and crawls over them in the night.

“It’s terrifying,” said filmmaker Paul Taitt of Hartford. “A lot of people we interviewed were convinced they were going to die.”

Taitt and film partner Andrew Barnes collected more than 62 hours of video for their documentary on sleep paralysis, a little-explored phenomenon that leaves people frozen in bed, unable to move or communicate and sometimes subject to frightening visions. They interviewed a Harvard Medical School psychiatrist and a Massachusetts monk, and they hit the streets asking people at random: Has this ever happened to you? A surprising number said yes.

“Nobody talks about it and one in five people around the world have had this or will have it in their lifetime,” Taitt said.

One theory: It’s the result of a physiological problem. The body is awake but the brain’s motor sensory skills haven’t switched back on. “The other side of the coin, the side we’re interested in, a lot of people believe this is a real spiritual phenomenon,” Taitt said.

Specifically, demons.

‘A very strange subject’

Eighty percent of sufferers see entities. They claim events can last as long as 20 minutes. There’s no conspiracy that keeps it from being talked about, Barnes said, but there’s definitely a stigma.

“You mean you’re seeing things in the night? That’s not really a good thing to admit in our culture,” he said. “We are going to change the way the world sees this. People have it. It’s not something to be shunned.”

In addition to talking to Mainers, including a Bangor sleep lab technician and a Wilton psychiatrist, the pair traveled to Penn State to interview Professor David Hufford, author of “The Terror That Comes in the Night,” who introduced the phenomenon to a broad audience in 1982.

“It is a very strange subject. I’ve been involved in about a half-dozen documentaries on the subject over the last few years,” Hufford said from his home this week. “Most of them I’ve found disappointing. These guys are the most serious, and I think sensible (in their approach).

“It’s a topic that’s sensational as it is. You really don’t need to add bells and whistles to it.”

Hufford drew a loose parallel between sleep paralysis and near-death experiences. Before the 1970s, having a near-death experience was thought to be a sign of a serious mental illness. No one talked about it – and those experiences were largely positive, he said.

For the film, Barnes also tried to interview dozens of members of the clergy who, thus far, have been reluctant to go on tape, but who made their feelings clear.

“Prayer tends to make this stop. Invoke your god, it generally stops – that’s what the subjects, the victims, were saying,” Barnes said. “From the perspective of the clergy, this is definitely demons.”

‘I heard the voice’

Taitt shoots corporate video and works in design by day. Barnes, from Farmington, is a teacher who coaches students on aspirations. With their wives, Heidi Taitt and Sue Gordon, the four formed Soul Smack production company. Work started on their first film eight months ago. Soulsmack.com will go live Saturday with forums, outtakes and behind-the-scenes downloads. They plan a soft release of the new DVD via the Web site on Halloween. It will also be available at Liquid Sunshine in Farmington for $9.95.

They’re still working on the final 60-minute cut. The goal, Taitt said, is to spread the word that such a thing exists, to get people talking and to stop misdiagnoses such as psychosis.

“They definitely could be entities from other realms. These are attacks,” he said. At the same time, “We’re not telling people what to believe. We just open up the film and people are telling you their stories.”

Barnes has never experienced sleep paralysis. Taitt has three times.

“I’ve had it during the making of this movie. It was bizarre. It turned into an out-of-body experience which I did put on tape and I will probably put that on the Web site,” Taitt said.

“I saw nothing; I was pushed into the bed. Tremendous pressure. I heard the voice, whispering. I was definitely paralyzed.”

Soul Smack’s next documentary is on UFOs and alien encounters, planned for spring. They’re looking for people in Maine with sighting experiences, and for researchers and skeptics.