What makes a film scary? Is it how dread is used to instill a mood and pull the viewer in, regardless of the story? Or perhaps it is the story itself, and being able to identify with compelling characters in a terrifying situation. It could also be the idea that's implanted in your mind that makes you repeat over and over: "This could happen to me," or "It's only a movie."
Lake Mungo: the Scariest Mockumentary Ever Made
The Australian mockumentary Lake Mungo is, without question, one of the scariest films ever made. This is why.