Billy Bob Thorton plays the titular mall Santa, a perpetually unkempt loser named Willie. Along with his dwarf partner Marcus (Tony Cox), they work the Christmas season at a department store and then, on Christmas Eve, sneak into the store after it closes - I won't spoil how - and loot both the merchandise (Marcus has a list that's drawn up by his gaudy, normal-sized wife) and the safe, which Willie cracks. Last season they scored over $100,000 and Willie, who despises himself with an almost religious fervor and is perpetually drunk, vows he's "out." Marcus has heard it before, but a few months later we see Willie fulfilling his promise of moving to Miami. He's behind a bar cutting limes and pours a drink. Then, the real bartender shows up and throws him out. So when Marcus calls up with a mall scoped out in Arizona, Willie reluctantly re-dons his ratty Santa costume for another go.

There our amoral heroes find work at a mall looking to cut corners (and have a "real midget" in the act), run by the late John Ritter in a small, but wonderfully nervous role. Almost immediately, Ritter's manager realizes he's made a mistake, what with a Santa who loudly refers to his penis as a "f***-stick," and screws plus-size women in the dressing room on his break, and so he get help from security chief Gin (Bernie Mac), who takes his job so seriously he spends most of his time bemoaning the state of an American society that produces so many potential thieves.

The final important character is one named Thurman but credited as "The Kid" (Brett Kelly) -- a chubby, innocent little dork who lives with his one-foot-in-the-grave grandmother and is so desperate for a taste of the Christmas spirit and a father-figure that he latches onto Willie's Santa and even lets him shack up at his place when things get hairy at Willie's hotel. Kelly's casting is perfect. Where the hell did they find such an adorably repulsive kid? We see him with snot - realistic snot, not exaggerated Farrelly Brothers stuff - hanging from his nose on more than one occasion. It takes guts for a movie to show the dark, true side of kid boogers.

The director of all this madness is Terry Zwigoff, who, in his documentary Crumb, made one of the single most depressing movies I have ever seen, and last made indie darling Ghost World. His films all focus on characters who have gotten the proverbial short end of life's stick. In the previous two films the humor was dark and subsumed within a straighter drama, but Bad Santa goes for laughs, and no movie I've seen this year is funnier. What's more, though Zwigoff softens his anti-life stance just a bit for Bad Santa, he never once goes for schmaltz or middlebrow notions of proper Christmas etiquette. Willie remains a thoroughly despicable guy, even as he warms to this obnoxious little kid who won't shut the hell up. In some ways, it reminds me of an edgier, smarter Mallrats, in that it loves poking holes in America's love of neutered, safe mall culture with jokes about anal sex and venereal disease.

In this way, Bad Santa is a Christmas movie for people of all denominations. It's less a celebration of Christmas than a condemnation of it, and what it embraces is not the mysterious, ethereal spirit we're also supposed to be consumed with at holiday time but rather the importance of a family in the life of a child. Its requisite happy ending is still plenty dark while hitting a realistically warm note that doesn't sacrifice the integrity of the characters it has done a phenomenal job of creating.