He sees you when you’re sleeping. He knows when you’re awake. He knows if you’ve been bad or good, so be good for goodness’ sake.

This Christmas, you’d better watch out. But it’s not being put on Santa’s Naughty List that you should worry about. It's coming to the the attention of the Christmas demon known as the Krampus.

According to German folklore, the Krampus — taken from the German "krampen," meaning "claws" — is a hairy, horned half-goat/half demon that serves as St. Nicholas’ dark companion.

Rather than giving gifts, the Krampus likes to whack bad little boys and girls with a birch stick before snatching them up in his sack and either dragging them off to the depths of hell or tossing them into the freezing waters of the Alpine mountains (depending on who’s telling the story).

"These are all fables meant to teach a lesson," explained Michael Boynton, assistant professor in the Jacksonville State University drama department. "What legends can parents tell their kids to make them behave? I’m pretty sure this one would work."

In Germany, the Krampus comes to town just ahead of St. Nicholas, on the night of Dec. 5, which is known as Krampus Night. Dec. 6 is St. Nicholas Day, when German boys and girls look to see if the shoe they left outside the night before holds a present or a rod. It they find a present, the children will know they’ve been good and received a visit from St. Nicholas. But the rod means they’ve been bad and will soon hear the jangle of rusted chains, the calling card of the Krampus.

Originating in the German-speaking Alpines, the Krampus isn’t the only disturbing counterpart to Santa Claus. Other Germanic regions have Belsnickle and Knecht Ruprecht. France has Hans Trapp and Père Fouettard, and the Netherlands has the controversial Zwarte Piet, or Black Peter (which involves blackface).

"These figures date back to pagan celebrations of Dec. 22, the longest night of the year, that were later adopted for Christmas," according to a recent article in National Geographic. "Together, the Krampus-like figures and the bishop St. Nicholas — a more austere version of the American Santa Claus — held a kind of judgment day for children, where the punishments for being naughty were much more severe than a lump of coal."

Greetings from Krampus!

In the 1890s, the Krampus became something of a pop culture dark star when German greeting card companies began manufacturing Krampus Christmas cards in Germany and Austria. They were adorned with slogans such as "Gruss vom Krampus" ("Greetings from Krampus") or "Brav Sein" ("Be Good").

The trend soon spread to adult cards, in which the Krampus was portrayed as being rather naughty himself, carrying off women, drinking schnapps or even as an admirer with romantic intentions.

Though once forbidden by the Catholic Church, people in Austria and parts of Germany still celebrate Krampus Night by running the streets dressed as drunken devils, dragging chains and thrashing anyone who gets in their way with birch branches.

Oddly enough, Krampus Night — minus the devil costumes and beatings with sticks — is similar to the way Christmas was celebrated in Colonial America, which is why the Puritans banned Christmas. They nicknamed it "Foolstide."

"For most people, before the 1800s, Christmas was not a domestic quiet holiday," writes Stephen Nissenbaum in "The Battle for Christmas." "It was a holiday that was characterized by boisterous revelry. It was sort of like a combination of Halloween and New Year’s Eve and Mardi Gras."

Thus the attraction for young people running amok on Krampus Day. While it might be fun for those participating, to visitors visiting the hunting ground of the Krampus is nothing short of "pants-soilingly terrifying," wrote Jon Holmes in a travel essay for the Sunday Times in 2010. Holmes visited Salzburg in an effort to report on the "wildest Christmas party in the world."

"One minute I’m enjoying the snowy ambience of the seasonal stalls, the happy laughter of ice-skating children on the breeze and the smell of Christmas in the air, and the next I’m being beaten up by Chewbacca’s evil twin, who roars at my face then makes off after another poor soul who has caught his demonic attention," he wrote.

Krampus comes to America

This year, the Krampus has come to America in a big way.

"I don’t know why they didn’t come up with this sooner," said Boynton. "It’s perfect for a horror movie."

Boynton has just come from seeing the new movie "The Krampus," which opened the same weekend as Krampus Night.

From "A Krampus Carol by Anthony Bourdain" to a Krampus comic book to Krampus-inspired parties and parades across the country, it seems that Santa Claus’ dark companion is here to stay.

"One reason I think Americans are intrigued by the whole Krampus myth is because so many are getting sick of the saccharine Christmassy feel that the holidays have become," Boynton said. "People want to bring a little of that dark side in."

Contact Brett Buckner at brettbuckner@ymail.com.