This is one of my favorite holiday time folk tales! Who doesn't like the idea of those bad kids gettin what's coming to them!
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 forclaw (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.