This is December 5th, the day before the Feast of St. Nicholas. Traditionally, in Austria and surrounding regions, December 5th is Krampusnacht, dedicated to Krampus, one of St. Nicholas’s companions.
In some versions of the St. Nicholas legend, Santa Claus does not punish naughty boys and girls himself, but has an assistant do it. One such is the devilish Krampus, a hairy, horned demon with a protruding tongue, scourges naughty children with his bundle of birch branches or carts the particularly bad ones off to hell in the wicker basket on his back. Then Santa can deliver treats to the good children on the following day after Krampus has cleared out the riffraff.
In the 1890s, after the Austrian government relinquished control of the postcard industry, colorful postcards featuring Krampus became popular. Most are darkly humorous depictions of Krampus tormenting children like he’s auditioning for a role in Made in Abyss.
Krampus has enjoyed some popularity in American pop culture of late, mostly in the form of television references and low-budget horror films, though he also has one wide-release motion picture to his name: