Sanctuary Fighting back the darkness with style.

The Krampus
is St. Nicolas's dark helper. While good old St. Nick rewards the good
children at Christmas time, the Krumpus follows him with a sack and a
switch to punish or carry away the naughty children. Goat-horned,
furry, dresssed in chains and with a long forked toung this demonic
looking creature is the traditional stick to Santa Claus's carrot in
Germanic countries.

St. Nick has other helpers as well for scaring the naughty into being
nice: Plack Peter (Zwiete Piet), Knacht Reupricht, and more. They all
have similar jobs. Black Peter is said to be Santa's brother in some
traditions, who is Santa's opposite in all ways. He is tall and thin
with dark hair and a swarthy complexion, and he is the one who leaves
coal and switches for the bad children.

But the Krampus is the most frightening in both appearance and job.
Celebrated on or around December 6, Krampus festivals are a time for
men of the village to dress in scary horned Krampus masks and visit all
the houses with children demanding drinks and chasing the children with
switches to remind them to be good. These festivities are all in fun,
but the real Krampus wouldn't be so funny to run across.

For more information, try these links:

Wikipedia Entry

Krampus.com

German-American traditions

Monsterama

Found in Fiction:

Supernatural: Season 3, Episode 8, A Very Supernatural Christmas.
In this episode Sam and Dean are looking into a series of
near-christmas kidnappings. As they do thier research they run across
mentions of an Anti-Claus. Krampus and Black Peter are both mentioned
by Sam as he outlines what he has found to his brother.

Krampus: the Movie