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 supernatural as the presence of a malevolent entity.
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.
Several physiological and psychological conditions can account for reported experiences of shadow people. These include sleep paralysis, illusions, or hallucinations brought on by physiological or psychological circumstances, drug use or side effects of medication, and the interaction of external agents on the human body. Another reason that could be behind the illusion is sleep deprivation, which may lead to hallucinations.
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. Later that year, on October 1, 2001, Heidi Hollis published her first book on the topic of shadow people. On April 7, 2002, Hollis discussed this book on the Coast to Coast AM show and was invited back as a regular guest, which helped to further define modern beliefs in shadow people. Hollis described them as dark silhouettes with human shapes and profiles that flicker in and out of peripheral vision, and claimed that people had reported the figures attempting to "jump on their chest and choke them". She believes they can be repelled by 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.
In popular culture
- Shadow people, described as "Shadow Men", feature prominently in the 2007 novel John Dies at the End.
- The 2013 movie Shadow People depicts a 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".
- 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 paralyzed and possessed, and the character's dream self will turn into a shadow person.
- On October 22, 1977, the Hat Man shadow person appeared as a character in the "Shadowman" episode of the children's cartoon Dynomutt, Dog Wonder. 
- Ahlquist, Diane (2007). The Complete Idiot's Guide to Life After Death. USA: Penguin Group. p. 122. ISBN 978-1-59257-651-7.
- Shelley Adler (15 January 2011). Sleep Paralysis: Night-mares, Nocebos, and the Mind-Body Connection. Rutgers University Press. pp. 3–. ISBN 978-0-8135-5237-8. Retrieved 10 February 2013. "In the field of sleep research, this experience is termed sleep paralysis: an individual, in the process of falling asleep or awakening, finds himself or herself completely awake, but unable to move or speak…Frequently, he or she sees a shadowy or indistinct shape approaching and becomes increasingly terrified."
- Clare Oakley; Amit Malik (15 November 2011). Rapid Psychiatry. John Wiley & Sons. pp. 6–. ISBN 978-1-118-29418-5. Retrieved 10 February 2013.
- Herbert C. Covey (2007). The Methamphetamine Crisis: Strategies to Save Addicts, Families, And Communities. Greenwood Publishing Group. pp. 17–. ISBN 978-0-275-99322-1. Retrieved 9 February 2013.
- Michael Kinsella (17 May 2011). Legend-Tripping Online: Supernatural Folklore and the Search for Ong's Hat. Univ. Press of Mississippi. pp. 117–. ISBN 978-1-60473-983-1. Retrieved 9 February 2013.
- Bell. "Art Bell - Shadow People". https://web.archive.org/web/20010606215053/http://artbell.com/shadows.html.
- "Shadow People & the "Hat Man"". Coast to Coast AM. 2008-03-07. Retrieved 2013-04-25.
- "Shadow Beings". Coast to Coast. 2006-03-27. Retrieved 2013-04-25.
- Greg Jenkins (1 February 2005). Florida's Ghostly Legends and Haunted Folklore: South and central Florida. Pineapple Press Inc. ISBN 978-1-56164-327-1. Retrieved 14 November 2011.
- Luiz, Joseph. "Paranormal investigator holds book signing". February 18, 2013. Hanford Sentinel. Retrieved 13 March 2013.
- Extreme Ghost Stories. ITV. 2006. Episodes 1 and 2.
- Bergin, Nicholas. "'John Dies at the End' has limited showing in Omaha". March 07, 2013. Lincoln Journal Star. Retrieved 13 March 2013.
- Liebman, Martin (March 19, 2013). "Believe in the boogeyman? Prepare to die.". Shadow People Blu-ray Review. http://www.blu-ray.com/. Retrieved 7 April 2013.
- "Following Freeware: July 2014 releases". Adventure Gamers. 29 August 2014. Retrieved 30 August 2014.
- Nelson. "Shadow People". http://porkrhine.wordpress.com/2011/02/14/shadow-people/.