No ho-ho in ‘Bad Santa 2’

Billy Bob Thornton as the drunken, ne’er-do-well Willie Soke, a department-store Santa; Tony Cox as hot-tempered, elfin Marcus; and Brett Kelly as the adult version of chubby, bullied Thurman Merman.

The main addition to the cast provides the movie’s only spark, and that is Kathy Bates as Willie’s down-and-dirty mom.

For the record, the plot involves a Christmas-time plan by the Sokes, abetted by Marcus, to rob a dubious charity, headed by wealthy sex-pot Diane (Christina Hendricks), who, remarkably, develops the hots for stumblebum Willie.

What “Bad Santa 2” is really about, though, is an attempt to tickle your devilish side, and in a day when outrageous comedy is omnipresent, that’s tough to pull off.

After a while, the avalanche of crude sex jokes, alcohol humor, trash-talk insults and slapstick starts to work on your nerves.

The original writers (Glenn Ficarra, John Requa) are only credited in this sequel for “characters”; Johnny Rosenthal and Shauna Cross get the “written by” credit.

Zwigoff’s humor is razor-sharp and incisive, qualities missing from “Bad Santa 2.”

Walter Addiego is a San Francisco Chronicle staff writer.