Yeah, I said the same thing when I went to shirt.woot and purchased my latest. I bought it based solely on the art, oblivious to the fact that I was purchasing an Xmas related tee. Yep, that evil, goat-legged bastard is actually a part of Xmas. From wikipedia:
Krampus is a mythical creature who accompanies Saint Nicholas in various regions of the world during the Christmas season. The word Krampus originates from the Old High German word for claw (Krampen). In the Alpine regions, Krampus is represented by a demon-like creature accompanying Saint Nicholas. Krampus acts in conjunction with Saint Nicholas; the latter gives gifts to good children, while the Krampus gives warnings and punishments to the bad children. Traditionally, young men dress up as the Krampus in the first two weeks of December, particularly in the evening of December 5, and roam the streets frightening children and women with rusty chains and bells. In some rural areas the tradition also includes birching by Krampus, especially of young females.
Modern Krampus costumes consist of Larve (wooden masks), sheep's skin, and horns. Considerable effort goes into the manufacture of the hand-crafted masks, and many younger adults in rural communities compete in the Krampus events.
In Oberstdorf, in the southwestern alpine part of Bavaria, the tradition of der Wilde Mann ("the wild man") is kept alive. He is like Krampus (except the horns), is dressed in fur, and frightens children (and adults) with rusty chains and bells, but is not an assistant of Saint Nicholas.
Jesus! Damn Germans. Though I'm admittedly intrigued by this particular brand of scare tactic when it comes to making children behave. If my parents had told me this thing was coming to my house on Xmas if I didn't behave, I would've been an angel all year, every year. There's also apparently a movie in the works, but so far all I can find is an "under construction" webpage.
So there ya go, Krampus. Who says you can't learn anything from shirt.woot? I certainly did.