Cheeky stuff. A fake, found footage mockumentary, which you can see as a variant on Blair Witch Project or This Is Spinal Tap, at your discretion. Essentially, a bunch of film students are making a documentary about bear hunters, and get interested in this one guy who all the other hunters say isn't one of them and thus must be a poacher. So the film crew try and interview him, and he rebuffs them, acting all mysterious. This only intrigues them more, so they tail him, and film him going about his business - which turns out to be hunting trolls.
Norway, it seems, has trolls. These are wild creatures who live in remote areas, usually having nothing to do with humans, but occasionally straying into settled areas, where they cause all kinds of bother, so the government calls in Hans, their troll hunter, who takes care of it, then the government cover it all up by framing a bear. Lately, though, it seems that the trolls are restless, and Hans is getting brassed off with the shitty working conditions, so he agrees to let the film crew film his work. So we're off hunting trolls, and investigating why there seem to be so many of them about right now.
The joy of this is the same joy as This Is Spinal Tap; it's played straight, but the subject is so ludicrous that it's hilarious. The trolls make it funny. They're funny because this isn't a case of doing the horror film thing of taking a legendary monster, but giving is a cool, modern, scary redesign; these are the big-nosed flappy-eared trolls from storybooks, with all the mores and behaviours that implies. Which is not to say they're not bloody impressive when in action, in fact, that's what really funny - they look absurd, but are 15 foot tall, roaring and crashing about the place, smashing trees, eating people and generally causing utter mayhem. Hans, meanwhile, treats this ludicrous situation in a stoic, morose, matter of fact way, reminiscent of someone who tracks badgers in a BBC wildlife documentary.
So, there you have it; part monster movie, part snarky satire, all tremendous fun. If there's a complaint, there's occasionally sequences in which we're driving around in cars too much, and seeing too few trolls, but when it all kicks off, it's absolutely worth the wait.