[1] A number of religions, legends, and belief systems describe supernatural entities such as shades of the underworld, and various shadowy creatures have long been a staple of folklore and ghost stories, such as the Islamic Jinn and the Choctaw Nalusa Chito.
[3] The first time the topic of shadow people was discussed at length on the show was April 12, 2001, when host Art Bell interviewed a man purporting to be a Native American elder, Thunder Strikes, who is also known as Harley "SwiftDeer" Reagan.
[10] Shadow people feature in two episodes of ITV paranormal documentary series Extreme Ghost Stories, where the phenomenon is described as a "black mass".
A sleep paralysis sufferer may perceive a "shadowy or indistinct shape" approaching them when they lie awake paralyzed and become increasingly alarmed.
Finally, visual hallucinations, such as those caused by schizophrenia and bipolar disorder, may appear to be shadowy figures at the edge of peripheral vision.