So far at Venice this year, we’ve had a film about the Srebrenica massacre, a Nazi documentary and films about grief and marital meltdowns, all of them serious and earnest. The only thing Mandibules is serious and earnest about is making a highly entertaining, politically incorrect comedy.

The premise is simple: two halfwit friends find a giant fly in the trunk of a car and decide to train it to commit bank robberies. Coming in at a brisk 77 minutes, this film knows just how far it can take the story before it runs out of laughs.

The hapless pair in question are Manu and Jean-Gab (Gregoire Ludig and David Marsais, respectively, who are both a hoot), who bear a striking resemblance to other cinematic dopey duos, most obviously Bill and Ted,and Lloyd and Harry in Dumb and Dumber. With their silly handshake and ‘Toro’ catchphrase, they act like feckless teens. There are echoes of Wet Hot American Summer here, for these are actually grown-ass men saddled with adolescent brains.

The film opens with Manu sleeping on the beach, his sleeping bag getting washed by the incoming tide. Asked to pick up a suitcase and make a delivery, Manu steals a beat-up Mercedes, picks up his pal and off they drive. They veer off course when they hear thumping and buzzing from the boot. On discovering the fly, the friends conjure up plans for how they could make money from the fly and this takes them off course and on some adventures that include a man in a caravan, a hidden cache of money and lots of cat food. Most of the pair’s problems arise from their sheer idiocy and inability to follow anything through, whether it’s frying pork chops or picking up some groceries.

When Manu is mistaken for an old schoolfriend, the two men are whisked off to a holiday home by the owner, her brother and a pair of pals. One of these friends is Adele Exarchopoulos, whose character is given an outrageous impairment incurred following a head injury. Director Quentin Dupieux is treading on thin ice here, for there will surely be an outcry from some quarters at Exarchopoulos’s borderline offensive portrayal. But she is excellent as the nutty mate who sees through the men and meets a terrible end.

Like Dupieux’s previous feature, the exquisite Deerskin, there are elements of comedy and horror, the audience finding itself laughing at things that are normally taboo. But this time the director has veered more on the side of comedy, much of which is more obvious than the surreal humour of Deerskin. As with his previous film, Dupieux has taken on a variety of roles: not happy to merely direct, he is credited with the writing, cinematography and editing. Basically, he’s a one-man filmmaking machine. And what a machine! His stories are a joy and he is proving to be a really singular filmmaker and distinctive storyteller. He shows the absurdities of human life, which often seems tragic, but with Mandibules he highlights the simple pleasure that true friendship can bring.