Near the climax of the film, we have Heather's apology scene, arguably the most famous scene in the entire movie, where Heather, while taking a video of herself, apologizes to Josh and Mike's mothers for urging them to come along into her project. You can see fear frighteningly clear in Heather's tear-filled eyes when she hysterically believes that she's going to die in the woods.
The sequel reveals just why they were hearing Josh's voice in the distance. The witch can imitate the voices of those she's taken in order to trick people into coming to her.
Even before they enter the woods, the students' humorous interviews with the Burkittsville townsfolk feature some pretty spooky local ghost stories and surrounding the Blair Witch legend.
The scene when Mike reveals he kicked the map into the creek earlier in anger — after Heather and Josh have spent a whole day arguing about who had it last — is some pretty harsh real-life horror.
Walking in one direction all day and ending up at that SAME LOG.
The area of the woods full of human-shaped effigies made of sticks.
Shortly after this, Mike is so terrified he just starts desperately screaming for help in the dead silent woods. It's clear he's reached a Despair Event Horizon.
How about the VERY last shot, after the camera is dropped? Is that part of the rocks, or a face-up dead body partly hidden by the stone wall? Also, it's pretty safe to assume something grabbed Heather, causing her to drop the camera.