Not, as advertised, the scariest movie ever made, but certainly among the most deeply unnerving; imagine Jaws without the boat, its trio of protagonists frantically treading water, watching a fin that's content for some time merely to circle and circle and circle the swimmers at a distance that's slowly but perceptibly diminishing. There are a few scattered moments of genuine horror, yes, but even these are either implied or ambiguous (not since Bill Pullman was swallowed whole by a pitch-black room in Lost Highway has onscreen darkness been used to such nightmarishly disturbing effect); the film is less about the titular bogeyfemme than about its characters' rapidly disintegrating psyches, so much so that I came out both times thinking not of The Texas Chain Saw Massacre or Psycho but of Sartre's No Exit. Myrick and Sanchez milk their gimmicky premise for all that it's worth, but what ultimately makes the picture more than just an impressive stunt is the gut-twisting immediacy of the central performances, Donahue's achingly believable combination of headstrong self-confidence and rampant insecurity in particular. It's Method acting at its most elemental, proof that sometimes the best way to appear exhausted on-camera is to eschew sleep the night before shooting; Olivier, were he still with us, would probably kindly suggest that the film's young cast might prefer to try acting, but I simply can't imagine any thespian, no matter how gifted, emerging from her trailer after a good meal and a long nap and managing to equal Heather's wide-eyed, snot-nosed, bone-chilling video apology. This, let us hope, is the future of ultra-low-budget digital cinema: ambitious, intelligent, unaffected, riveting. No doubt the net will soon be awash with fervent arguments about exactly what occurs in the film's frantic final seconds (hint: pay close attention to the first-reel interviews), but include me out -- I'll be too busy packing my belongings and studying my world atlas, trying to locate the metropolitan locale furthest from any area that could remotely be construed as "wooded."