Fun Size (12A)

Hallowe'en in US cinema is generally an occasion for teenagers to be stalked and slashed. Nickelodeon films have tried to reposition it for this family-oriented teen comedy, only now the victims are the audience that has to sit through it.

Victoria Justice plays high-schooler Wren, fed up with a fat-brat brother (Jackson Nicoll) who plays pranks, and a recently widowed mum who dresses like Britney and dates a 26-year-old. Wren wants to go to a party thrown by the coolest kid in school but instead gets landed with minding the pesky sibling, whom she promptly loses amid the Hallowe'en chaos.

The mixture of teen sexuality and stranger-danger nudges would look odd in any comedy – and downright outlandish in a comedy without a single decent laugh. Jane Levy as Wren's cynical best friend times her snitty comments nicely, but it's slim reward for the grotesque capering elsewhere.

Johnny Knoxville, of Jackass fame, tries to disguise himself in a blond wig, without success. He must know what we do, that this is stupid and clueless and no fun at all – in any size.