The Blair Witch was a supernatural American hoax that was proven to be orchestrated by adolescents. Sebastian Chiltern mentioned it to the Eighth Doctor in 1883. (PROSE: Camera Obscura)
Behind the scenes
The Blair Witch is a fictional ghost from the Blair Witch horror franchise. According to I, Who 3, the mention of the Blair Witch in Camera Obscura is a mistake and Lloyd Rose had intended to instead make reference to the real life Bell Witch legend.