On the seventh day of Christmas, my true love watched with me....
Don't Open til Christmas (1984)

If you ever get fed up with Christmas horror films with psychopathic Santas -- the worst I've ever seen is To All a Goodnight -- then check out this dreadful British picture, in which a psychopath (Alan Lake) murders old gits in Santa Claus outfits.

On the eighth day of Christmas, my true love watched with me...
Silent Night, Deadly Night (1984)

Though there were enough homicidal maniac Santas in movies before 1984 to form a football team -- with reserves -- this was the picture that excited pro-Christmas protesters to picket at the sacrilege of depicting old Kris Kringle as a murdering lunatic. Maybe it was the scene where Linnea Quigley gets impaled topless on some reindeer antlers. All the fuss didn't stop Silent Night, Deadly Night from having four sequels. For true perversity, I recommend the immediate follow-up Silent Night, Deadly Night Part II (1987), which cheekily recycles about an hour of footage from the original to pad out the minimal new story, but does run to a wonderful sequence -- blatantly ripped off in Scary Movie -- as the vigilante killer is taken to see a film about a murdering Santa ("that's the worst idea for a film I've ever heard") and gleefully takes a knife to some clown who talks throughout the picture.

On the ninth day of Christmas, my true love watched with me...
Gremlins (1984)

A classic -- for Phoebe Cates' "and that's why I hate Christmas" speech alone. The studio wanted it cut, but Joe Dante insisted it stay in.

On the tenth day of Christmas, my true love watched with me...
The Addams Family (1991)

The opening of the film brings to life Charles Addams' wonderful Christmas spirit cartoon, in which his gruesome family celebrate their own variety of togetherness by pouring boiling oil onto the heads of a parcel of merry carol-singers.

On the eleventh day of Christmas, my true love watched with me...
P2 (2007)

Rachel Nicholls is trapped in a parking structure on Christmas Eve by a lunatic stalker (Wes Bentley) who wants to have take-out turkey with her and is going to torture her nasty boss to death as a present. There has to be a Christmas-themed torture porn/abduction movie, and this is it.

On the twelfth day of Christmas, my true love watched with me...
The Devil Doll (1936)

This is the one about Lionel Barrymore escaping from Devil's Island and teaming up with mad scientists to wreak vengeance on his tormentors -- he drags up as a little old lady and opens a toyshop, selling shrunken, hypnotised human beings as dolls who also work as assassins. The best scene has a miniature killer smuggled into a victim's home as a Christmas present for a little girl, then coming to life while tied to the tree and scurrying through the wrapped gifts to leave a nasty surprise come Christmas morning.