Available on DVD “Trollhunter”

Written and directed by André Ovredal, Trollhunter is a deft little mockumentary in the vein of The Blair Witch Project, Cloverfield, and Paranormal Activities, purportedly real exercises in which dummies with video cameras come up against the supernatural. Here we get three naive communications students at Volda University — cameraman Kalle (Tomas Alf Larsen), sound-girl Johanna (Johanna Morck), and on-air talent Thomas (Glenn Erland Tosterud) — who follow a grizzled Great White Hunter type named Hans (Otto Jespersen) into the wilds of upper Norway.

They think he’s a poacher. In fact, he’s the Norwegian government’s one-man Troll Control squad, and he’s getting awfully burned out. The hours are terrible and the benefits stink worse than the trolls. The students don’t believe a word of this until they flick on the night vision while Hans flushes his quarry and — well, let’s just say the movie’s special effects are as goofily impressive as the camerawork is cheap.

Trollhunter works on a number of levels, the most immediately satisfying of which is the office-place comedy (one that just happens to take place miles from civilization). Hans has an officious bureaucratic boss named Finn (Hans Morten Hansen), who tries to blame all those half-eaten sheep on bear attacks. This leads to a blissfully funny sequence in which the Polish day laborers hired to plant a dead bear deliver the wrong kind by mistake, leading Finn to improvise desperately in front of the press. To quote one of the Poles, “Why problem make when you know problem have you don’t want to make?’’ This turns out to be useful advice when dealing with inept government conspiracies.

Ovredal’s script also codifies for the movies centuries of troll lore, which means an HBO dramatic series can’t be far behind. Hans asks if the three students are atheists, since it turns out trolls actually can smell Christian blood. (It doesn’t help to lie about this.) Trolls also turn to stone when exposed to sunlight or its ultraviolet equivalent, a process explained by a helpful lady veterinarian in spurious biological detail.

The bit about hiding under bridges? True. We’re also introduced to various subspecies: the Tosserlad, the Ringlefinch, the Jotnar. All are ugly, huge — the Jotnar especially so — and not terribly bright. In fact they’re rather sweet, or would be if they weren’t given to stomping on things.

The momentum stalls in the last half, and the movie doesn’t end so much as roll slowly to a halt. Once again, material for a great short film has been expanded to feature length at its peril and ours. Still, this is clever stuff and surprisingly engrossing on its own terms. What Trollhunter isn’t is particularly scary, but in its defense, it’s not trying to be. After a certain point you realize it’s simply another monster movie in which the monster is us.