Along with music, dancing and folklore, this year's edition of The Christmas Revels features a glimpse of Santa's dark side.

The Revels - an interactive holiday performance with music at its heart - is set this year in 19th-century Bavaria, where holiday traditions range from the familiar to the surprising.

It seems the Bavarian Santa, Sankt Nikolaus, has an alter ego, Knecht Rupprecht.

"If you pulled Santa Claus apart into the good Santa and the bad Santa, Rupprecht is the darker side of St. Nick," says Mary Lynn, director of the Revels. "He wants to keep track of who's been bad, and he wants to switch the bad children and give them coal."

"He can be scary," she adds. "I have a German friend who was afraid of Rupprecht. But ours isn't going to be scary. He's going to be funny."

While the show has some characters, it's built around a large chorus. Lynn says those new to it aren't always sure what to expect.

"It's always a conundrum for people because it's an unusual kind of theater," she says. "Sometimes, people think it's a choral concert, or other people get it mixed up with a group that used to do an Elizabethan feast. And some people think it's a festival. But it is theater.

"Music is the heart of it," she adds. "It is short on plot, long on theme. It's just an unusual thing."

The Puget Sound Revels, which has put on the Christmas Revels in Tacoma since 1994, is part of a national network of Revels groups. Each group creates its own shows, but all follow a similar format.

The event invites audience participation in the singing and dancing at key points.

"It's more than just people getting together and singing," says Karen Konrad of Dupont, who's in the chorus. "And it's intergenerational, which is lovely. You have the wee ones singing along with the elders."

The Revels are carefully researched and incorporate the customs of the time and place chosen for each production, Lynn says.

For this year's Bavarian theme, that means Sankt Nikolaus, Knecht Rupprecht, a shoe-slapping dance called "Schuhplattler" and a procession of masked drummers called the "Perchten" procession - and the good old Christmas tree.

"In Germany, their Christmases are very Christmassy," Lynn says. "A lot of our modern traditions come from there."

A few elements do return from year to year regardless of theme, including the poem "The Shortest Day," by Susan Cooper, and the Sussex Mummer's Carol that ends the show.

Celebration, not re-enactment, is the goal.

"We're re-creating a celebrating village on stage," Lynn says. "Everyone who comes sort of has a sense that ‘I am part of this celebrating village.'

"This is how you're marking that dark time of the year with your village, with your community."

The Christmas Revels

Saturday, Dec. 17, 2 and 7:30 p.m.; Sunday, Dec. 18, 1 and 5:30 p.m.; Tuesday, Dec. 20 and Wednesday, Dec. 21, 7:30 p.m.
$12-$27, $12-$23.50 for students and seniors, $12-$19.50 for children
Rialto Theater, 901 Broadway, Tacoma
pugetsoundrevels.org or broadwaycenter.org