Victor Sharrah is one of the very few people in the world who suffers from the rare disorder. But, with his help, researchers are finally beginning to better understand it. 

One morning, he awoke to a terrifying experience; the faces of everyone he came into contact with had demonic features, per NBC News. 

They also had deep groves in their chins, cheeks, and foreheads, all of which frightened the Tennessee man.

He went on to express how terrifying the first moments were, saying, “You can’t imagine how scary it was.”

Upon relating to his friend what he was experiencing, they suggested he may be suffering from prosopometamorphopsia, or PMO, per NDTV.

The disorder forces people to experience distortions in the faces of everyone they come into contact with, which gives them demonic features. 

However, what’s unusual about Sharrah’s disorder is that the distorted faces only appear in person. But not when he looks at faces on the internet or in photographs. 

Researchers believe it is caused by problems in the part of the brain that handles facial processing. Symptoms can last from a few days to a few weeks and, in some cases, years. 

Doctors believe this may have brought on the disorder. Another option goes back over 10 years when Sharrah fell and hit his head fairly hard on the ground, which left behind scarring on his brain.

Researchers at Dartmouth College created several digital representations based on Sharrah’s descriptions before posting them online. 

They instructed Sharrah to compare the photograph to the person standing beside them before using image-editing software to produce the images based on Sharrah’s description. 

Some people “have seen face distortions since they remember, since they were a child,” Mello said. “For them, at least, it’s impossible to find a single event that was responsible.”