The dirty, unstable, angry Christmas character who brings presents & punishment to children each year.
Unhinged Santa
Belsnickel is a Christmas tradition that comes from south western Germany. He visits each year, typically operating alone, usually in lieu of Saint Nicholas / Santa Claus. His name is a combination of “bels” (fur) and “nickel” (a diminutive version of Nicholas, from Saint Nicholas) – “Nicholas in Furs” essentially. He’s dirty, dressed in furs, sometimes wearing a mask, maybe has antlers, twigs, leaves, and arrives on Christmas Eve carrying a sack of treats along with a wooden switch/whip.
He announces his arrival by rapping on a window or a door. Like Santa Claus he comes to reward the good children and punish the bad ones, but unlike Santa he is unpleasant and unpredictable. He is loud, angry, and prone to outbursts. In days gone by Belsnickel would throw treats to the ground for the good children and hit the bad children with a switch. Even the good children, if they moved too fast for the treats, might get hit with the switch.
Pennsylvania Dutch
Belsnickel came to America with German immigrants in the early 19th century and in particular to Pennsylvania. A bit of a misnomer, the Pennsylvania Dutch weren’t from the Netherlands but were from the same German speaking Palatinate region as Belsnickel. Among the rural Pennsylvania Dutch the tradition of Belsnickel continued.
In 19th century America Belsnickel led to “Belsnickling”, the custom of dressing in masks & costumes going door to door on Christmas Eve. Like mumming, or the Mari Lwyd tradition in Wales, Belsnickling participants would cause lighthearted mischief seeking coins & treats. By the end of the century masks for Belsnickling would even outsell Halloween masks in some areas.
Over the years Belsnickel changed with the times. Instead of arriving on Christmas Eve he can arrive anytime during the Christmas season. The influence of Santa Claus (and the decline of corporal punishment) has toned down Belsnickel’s behavior. He’s still unpredictable but instead of smacking children he is more likely to ask them if they have been bad or good, giving them presents or a scolding.
Post WWII, and the influence of pop culture, Belsnickel lost popularity to Santa Claus but has seen a bit of a resurgence in recent years. In 2012 the ninth season of The Office introduced Belsnickel to a wider audience with the Christmas episode of Dwight Christmas.
Added info: Belsnickel is one of many Christmas reward & punishment characters. Père Fouettard, Knecht Ruprecht, Zwarte Piet, and of course Krampus all are folk traditions that play a part in the Saint Nicholas / Santa Claus story.