While the author Heidi Hollis is credited with coining the phrase in 2002, I’m not sure anyone could come up with a better term for what have come to be known as shadow people.  

In the interest of full disclosure however, I should probably point out that a short time later Hollis went completely off the reservation even for a paranormal investigator.

Her shadow people became, at various times, astral travelers, time travelers, extraterrestrials, and visitors from other dimensions.  In fact many of her followers were over joyed when her shadow people became plain old demons.  In the end she settled on evil spirits doing battle with God who could only be vanquished through prayer, and I don’t think anyone was surprised when her next book was called “Jesus Is No Joke”.

All that aside, those of us who have had these encounters would tell you that a shadow person is primarily seen via peripheral vision and is exactly what you would think by its name.

While it’s the movement that catches one’s eye, in the end it appears to be something darker than the dark. Sometimes it has a vaguely human form, and other times it’s just a mass.  Often, like most EVP's, the shadow isn't visible until reviewing the video or photographs.

Personally, of everything I've seen, heard and felt nothing has ever given me the creeps quite as much...