The Blair Witch Project: 7 Most Compelling Fan Theories
7. Mary Brown Is The Blair Witch
Early on in the documentary footage, when the trio are compiling interviews with the Burkitsville locals, they visit an eccentric old recluse named Mary Brown who recounts a supernatural encounter from her childhood. Of course, they instantly dismiss Mary as a "lunatic", as Heather later describes her.
This is the most superficial of the popular theories out there about The Blair Witch Project, and in truth there is very little to back this assumption up. On first viewing, a significant number of people likely assume from Mary Brown's fleeting minute of screen time that she will ultimately be revealed as the titular entity, based entirely on the fact that she bears a likeness to the stereotype of the decrepit old hag (frail; old-fashioned attire; pointed nose and chin). Honestly, that's probably why Myrick and Sanchez put her in the film.
However, as supporters of this theory correctly point out, Heather remembers that Mary Brown had warned them of "something about a pile of rocks" when they discover that such formations have mysteriously appeared around their tent. It is also frequently noted that the string binding Mary's gate is similar to that used to tie the stick figure symbols that also crop up in the woods.
Even if she isn't actually Elly Kedward herself, rather an unhinged fanatic unhealthily obsessed with the local legend, it's not too much of a stretch to believe that she is responsible for the rocks and sticks. It's the human teeth and severed tongue that are a touch more concerning.