Vindication for the grainy, jiggly image of the handheld camcorder, the mockumentarist’s best friend and a corner-cutting, cost-cutting device for any purpose. The premise — the excuse — is the making of a video souvenir at the going-away party for a Manhattan yuppie, the night before his departure to a plum job in Japan; and the product, by its very nature, is an exercise in subjective camerawork as extreme as, though not as strained as, Robert Montgomery’s anomalous Lady in the Lake, 1946. Amateurish by design, with the camera in the hands of a conscripted novice, the evolving souvenir is all we get for the first twenty minutes of the movie, leading to suspicions of padding in what turns out to be barely an hour-and-a-quarter movie. It might have led also to squirms of impatience if the document had not been labelled at the top as the property of the Department of Defense, retrieved from the “area formerly known as Central Park.” You know something’s coming. What finally comes at the 20-minute mark, revealed bit by bit, fleeting glimpse by sidelong glance, proves to be a distant relative of Godzilla — the yuppie didn’t have to go to Japan; Japan came to the yuppie — a composite creature combining on a gargantuan scale the slimy squid, the plucked chicken, and the skinned calf, shedding like fleas some spidery creatures of more human dimension. (Additional aerial footage from a cable news network lends some helpful perspective.) It is quite understandable and quite realistic, in the post-Rodney King era, that the party videographer would choose to keep the tape rolling as his small circle of friends fights to survive the night (“People are gonna wanna know how it all went down”), and the shaky, sketchy coverage of the events only enhances their immediacy and intensity. And the monsters themselves, even allowing for their extended tendency to play peek-a-boo, are expertly realized. This is Blair Witch on a looser budget. Lizzy Caplan, Jessica Lucas, T.J.Miller, Michael Stahl-David, Mike Vogel, Odette Yustman; directed by Matt Reeves. (2008) — Duncan Shepherd