The Blair Witch is the most terrifying villain in film history because, ultimately, the audience never *saw* her.  She’s an unknown entity.

And then there’s the sick implication at the very,very end of The Blair Witch Project movie that Heather actually did see her. Off-camera, of course 

And Heather fucking lost it and kept screaming and screaming for her life. Dear God, her insane yelling in the final few seconds of that film. It terrified me at 14. I didn’t sleep for days.

The point of the Blair Witch: Your imagination does all the work for you. More than any filmmaker ever could.

It’s about the individual and their very,very worst nightmare