CANNES (AFP): Shape-shifting home invaders terrorise a wealthy family of five in a Dutch thriller tinged with black comedy that sent a shiver through Cannes Sunday.

"Borgman" by Alex van Warmerdam is a dark fairy tale that explores the guilty conscience of a cosseted modern wife living in a luxurious suburban home like a gilded cage.

An opening sequence sees feral-looking men emerging from secret chambers hidden underground in a wood, while an armed search party led by the local priest tries to hunt them down.

A bearded figure called Borgman, straight out of a Grimm Brothers' tale, improbably pulls out a mobile phone and tries in vain to contact his fellow forest-dwellers to warn them, in an early scene that drew laughs.

Borgman emerges from the trees and walks up to the door of a sprawling contemporary house. He knocks and says he needs a bath as it's been ages since he washed.

The media executive home owner, Richard, demands he leave, but his wife, Marina, takes pity on Borgman and later secretly lets him in to wash up.

He quickly insinuates himself into the home, appearing as a dreamlike figure to their three children and mesmerising them with spooky stories.

His forest friends also turn up, in the form of greyhounds prowling the house and sniffing the pretty Danish au pair while she's fallen asleep in the bathtub.

Meanwhile Marina starts having recurring violent nightmares in which Richard tries to kill her.

She is attracted to the mysterious Borgman, who has taken pains to kill their gardener, put on a disguise and get himself hired to tend their grounds in the dead man's place.

The increasingly irritable Marina scolds her husband for buying her an expensive necklace, saying she feels ashamed of their wealth while others in the world suffer in poverty.

"We can't help we're from the prosperous West," a baffled Richard tells her. "It's not our fault."

And Marina flies into a rage when their odd young daughter Isolde destroys her teddy bear, scolding "someone sewed it by hand, possibly a child," in another pitch-black laugh line.

Borgman and his friends launch a final assault on the family, the body count rises and in a shocking finale, Marina is forced to choose between the forest demons and her husband.

The actress who played Marina, Hadewych Minis, said she saw her character as a perfectly normal European wife and mother who is lured to the dark side by the pressures of everyday life.

"That's what happens when magic comes over you," she quipped.

Van Warmerdam said consciousness was full of dark surprises that could sneak up on the best of us.

"I read something about the Marquis de Sade... that your mind is much bigger than you think and that there are rooms you've never been before, maybe rooms where there are nasty, creepy things to find," he told reporters.

"That was more or less the starting point of this movie."

It was the first Dutch film in competition in nearly four decades at the world's top cinema showcase and one of 20 pictures from around the world vying for the Palme d'Or top prize.

Jury president Steven Spielberg was grilled by a Dutch reporter at the start of the festival whether he was familiar with Van Warmerdam, best known for European arthouse hits such as "Grimm" and "Waiter".

Spielberg admitted he was not but laconically added: "We'll become aware of the maker if the film causes us to be made aware of the maker."