Every year, foul-mouthed alcoholic Willie T. Stokes (Billy Bob Thornton) teams up with his dwarf partner, Marcus (Tony Cox), to become employed as a mall's Santa and elf, only to case the joint after closing on Christmas Eve. With the money Willie cracks from the safe, he is able to live out the other eleven months of the year in a drunken, semi-blackout haze--not that he let's employment stop him from doing just that in the remaining month of December. This Christmas, Willie and Marcus' victim is a mall in Phoenix, Arizona, where a department store manager (John Ritter) becomes suspicious; a security chief (Bernie Mac) turns out to have a shady ulterior motive; a wily Santa fetishist named Sue (Lauren Graham) falls for Willie; and an unlikely friendship forms between a chubby, bullied 8-year-old (Brett Kelly) and Willie, who moves in with him and his daffy grandmother (Cloris Leachman).

Written by John Requa and Glenn Ficarra (2001's "Cats & Dogs"), "Bad Santa" is wildly offbeat in its tone and subject matter, but unexpectedly traditional in its moralistic tale of a good-hearted child who brings cheer (or, at the least, something vaguely resembling it) to a desperately lost soul. The film is filled from end to end with an endless stream of four-letter words, all fluidly used to hysterical effect rather than extraneously, while hearty helpings of heavy alcohol abuse and extreme sexual situations further ensure that this is, indeed, a motion picture for adults. Seeing the drunk-off-his-ass Willie posing as Santa Claus and reacting in crude ways to the children on his lap never ceases to be priceless, nor does his explanation to Willie that he is in the dog house for sleeping with Mrs. Claus's sister.

Billy Bob Thornton (2003's "Love, Actually") is genuinely perfect as the terminally depressed, liver-damaged Willie, who walks through the movie with an "I don't give a shit" expression on his face and a glazed, booze-induced look in his eyes. Thornton is comic gold, yes, but he also develops Willie into a rather sad human being, one that feels three-dimensional but hopeless, headed for a destructive end. It is a fascinating character, and an even better performance. As the 8-year-old kid, whose name becomes the punchline of a joke when it is disclosed, Brett Kelly (2001's "Out Cold") is a born natural with a plausible childlike curiosity and innocence intermixed with a soulful personality. Much of the film's effectiveness hinges on Kelly, and he is up to the challenge every step of the way.

The supporting characters are a mixed bag blessed by superb character acto rs in the roles. Tony Cox (2000's "Me, Myself & Irene") gets strong comedic mileage out of Marcus, a dwarf playing an elf who uses his handicap as a threat toward the store manager when he tries to fire him. The way in which Marcus is used in the climax, however, is a disappointment, and his intentions become needlessly muddled. As the Santa-hungry Sue, Lauren Graham (2001's "Sweet November") is akin to a breath of fresh air, even if her character isn't quite developed as much as it should have been. Still, Graham herself excels at getting the viewer to almost understand the allure she sees in the sad-sacked, nasty Willie. And in his final feature film, the late John Ritter (1998's "Bride of Chucky") is his usual respectable self, handling his comic moments with precise timing, as when he tries to recount a sexual story without verbalizing the naughty words.

Take out the bad language, the sex antics, the drinking, the negative attitudes, and the occasional violence, and "Bad Santa" would be an ideal holiday offering for the kiddies, right alongside the delightful "Elf." By inserting all of these things, the movie has become an instant nightmare for any dim-witted parents who make the mistake of taking their children to see it. The point, I think, is that grown-ups deserve Christmas movies as much as anyone, even one's laced in puke, blood, and Jack Daniels. And if it unveils signs of heart and feeling by the conclusion, keep in mind it is still of the severely twisted variety. "Bad Santa" is the kind of rare perverse treat that John Waters would undoubtedly go crazy for. You will never look at Santa Claus in the same light again.