Deadly Little Christmas (2009): Yule Be Horrified!
The Carpenter that inspired Deadly Little Christmas is much more of the 'John' type than the 'from Galilee' variety as the film borrows heavily Michael Myers' origin tale. On Christmas morning, when Dad goes off to have some “special” Christmas cheer with the housekeeper, young Devin (Shane Carther Thomas) takes exception to their merriment. After stabbing the adulterous pair to death, Devin walks right out of the house, on a sunny California Christmas morning, with the bloody knife still clenched in his fist. Cut to fifteen years later and Devin, now a grown up Samuel Nathan Hoffmire (What’s the deal with casting people with 3 names to play this kid? Is it more serial killery?), has been a long term resident at the funny farm. When Devin’s mother (Felissa Rose) comes to visit him, he remains unresponsive and silent, but this year for Christmas, he’s decided to come home.
I couldn't find a trailer, but I did find a remix of the head stabbing scene that I found quite entertaining.