A trailer for the spoof film 'Siri: The Holiday Horror Movie' has caused a stir on YouTube and features a group of friends being hunted down and killed by their iPhones.

The trailer, made by RoosterTeeth, shows a group of friends who all get the iPhone 4S for Christmas; but after playing with the voice-activated personal assistant, Siri, they find that the phones are trying to kill them.

One character is killed after Siri directs him to drive into a wall and another iPhone attacks a woman in the shower in a scene reminiscent of the 1960 horror film Psycho.

Siri is an application on the iPhone 4S that can be used to set reminders, write emails and look up information by being spoken to. Apple engineers have included some jokes and references to films, too, and one of the most popular Siri questions is "What's the meaning of life?"

In the spoof trailer, which has been viewed nearly 500,000 times in two days, Siri replies with "Life has no meaning. It's true, you're alive and then you die, you die, you die, die, die..." before going on the rampage.

Siri goes on to stab another character, after saying the popular Apple phrase "there's an app for that" and displaying a knife on the iPhone's screen.

The trailer has all of the classic elements of an American 'slasher' film and the ways in which Siri kills its victims get more and more surreal as the trailer goes on.

Siri is seen driving a car and trying to run someone over, dragging someone by the leg tying another to a chair with rope.