This is a clever one. The film is, more or less, wholly original, based on what one guess is a rough outline by Eduardo Sanchez and Daniel Myrick for the actors to work around. The film works so well, though, because it models itself on every rubbish yet believable ghost story weve ever heard, and doesnt even bring it to screen; it lets us imagine it all instead, which makes the whole thing feel painfully real. If this were, ever (god forbid), turned into a book, the book would read something like this- Heather heard a small child laughing. She ran away from her tent yelling maniacally. It doesnt sound scary in the slightest, but the film is, and plays havoc with our innermost, innate, primal fears, aka the dark and the unknown. Its an original concept, and an original film, and the countless imitators, no matter how hard they try (Paranormal Activity, Im looking at you), can never match the brute force of this little original masterpiece.