Shadow person

A shadow person (also known as a shadow figure, shadow being or black mass) is the perception of a patch of shadow as a living, humanoid figure, particularly as interpreted by believers in the paranormal or supernatural as the presence of a spirit or other entity.

Myths & legends
A number of religions, legends, and belief systems describe shadowy spiritual beings or supernatural entities such as shades of the underworld, and various shadowy creatures have long been a staple of folklore and ghost stories.

The Coast to Coast AM late night radio talk show helped popularize modern beliefs in shadow people. The first time the topic of shadow people was discussed at length on the show was April 12, 2001 when host Art Bell interviewed Native American elder Thunder Strikes, who is also known as Harley "SwiftDeer" Reagan. During the show, listeners were encouraged to submit drawings of shadow people that they had seen and a large number of these drawings were immediately shared publicly on the website. In October that year, Heidi Hollis published her first book on the topic of shadow people, and later became a regular guest on Coast to Coast. Hollis describes shadow people as dark silhouettes with human shapes and profiles that flicker in and out of peripheral vision, and claims that people have reported the figures attempting to "jump on their chest and choke them". She believes the figures to be negative, alien beings that can be repelled by various means, including invoking "the Name of Jesus".

Although participants in online discussion forums devoted to paranormal and supernatural topics describe them as menacing, other believers and paranormal authors do not agree whether shadow people are either evil, helpful, or neutral, and some even speculate that shadow people may be the extra-dimensional inhabitants of another universe. Some paranormal investigators and authors such as Chad Stambaugh claim to have recorded images of shadow people on video.

Scientific explanations
Several physiological and psychological conditions can account for reported experiences of shadowy shapes seeming alive. A sleep paralysis sufferer may perceive a "shadowy or indistinct shape" approaching them when they lie awake paralyzed and become increasingly alarmed.

A person experiencing heightened emotion, such as while walking alone on a dark night, may incorrectly perceive a patch of shadow as an attacker.

Many methamphetamine addicts report the appearance of "shadow people" after prolonged periods of sleep deprivation. Psychiatrist Jack Potts suggests that methamphetamine usage adds a "conspiratorial component" to the sleep deprivation hallucinations. One interviewed subject said that "You don't see shadow dogs or shadow birds or shadow cars. You see shadow people. Standing in doorways, walking behind you, coming at you on the sidewalk." These hallucinations have been directly compared to the paranormal entities described in folklore.

Literature

 * Shadow people, described as "Shadow Men", feature prominently in the 2007 novel John Dies at the End. When they kill a person, that person is retroactively erased from existence, and history is rewritten as though they were never born.

Films & animation

 * An episode of the 1985 Twilight Zone series titled "The Shadow Man" dealt with a teenage boy who had a shadow person living under his bed. The episode portrayed the shadow man as fitting the "hat man" appearance commonly ascribed to shadow people and notably added to the shadow people mythology that shadow people can kill human beings but will not harm those whose beds they live under.
 * The 2015 documentary The Nightmare interviews people who suffer from sleep paralysis and stages their hallucinations with actors. Shadow people are mentioned several times, and appear in the reenactments.
 * The 2013 horror film Shadow People depicts a fictional sleep study conducted during the 1970s in which patients report seeing shadowy intruders before dying in their sleep. The movie follows a radio host and CDC investigator who research the story, and the story is claimed to be "based on true events".
 * Shadow people feature in two episodes of ITV paranormal documentary series Extreme Ghost Stories, where the phenomenon is described as a "black mass".
 * In Season 1, Episode 16 of Supernatural (2005) called “Shadow,” Sam, Dean, and John Winchester are attacked by a daeva— or a Zoroastrian demon that can only be seen as a shadow person.
 * In Disney's The Frog Princess, the antagonist summons shadowy figures to assist him in his schemes when hunteing the Frog Prince.

Video games

 * In the online game Deep Sleep and its sequels, shadow people have existed since the dawn of the human race and lurk in lucid dreams. Players who realize that they are asleep can be paralysed and possessed, and the character's dream self will be turned into a shadow person.