In Central European folklore, Krampus is a horned, anthropomorphic figure described as "half-goat, half-demon", who, during the Christmas season, punishes children who have misbehaved.

This contrasts with Saint Nicholas, who rewards the well-behaved with gifts. Krampus is one of the companions of Saint Nicholas in several regions including Austria, Bavaria, Croatia, Czech Republic, Hungary, Northern Italy, Slovakia, and Slovenia.

In recent years, the myth that the Krampus was the son of Hel, Norse goddess of the underworld, has been popularised on the internet, even appearing in articles in National Geographic and Smithsonian Magazine.

Although Krampus appears in many variations, most share some common physical characteristics. He is hairy, usually brown or black, and has the cloven hooves and horns of a goat. His long, pointed tongue lolls out, and he has fangs. Krampus carries chains and thrashes the chains for dramatic effect. The chains are sometimes accompanied with bells of various sizes.

Of more pagan origins are the 'Ruten', bundles of birch branches that Krampus carries and with which he occasionally swats children. The birch branches are replaced with a whip in some representations.

Sometimes Krampus appears with a sack or a basket strapped to his back; this is to cart off evil children for drowning, eating, or transport to Hell. Some of the older versions make mention of naughty children being put in the bag and taken away.

More Info: en.wikipedia.org