For many Christians, the period of 5 to 6 January is celebrated as Twelfth Night, the Feast of the Epiphany or Three Kings Day. It's the finale of the Twelve Days of Christmas, which begins on either Christmas Eve or Christmas day, depending on the tradition. More feasting, more music, more gifts exchanged... and more visits from supernatural beings.
One of whom is generally known today as Frau Perchta. The "Christmas Witch".
In Central Europe and particularly the alpine regions, she has a long history as a multifaceted goddess. In pre-Christian times she was known as a beautiful woman, often dressed all in white, who was a guardian of both human domesticity and the wild creatures of the forest.

She was tasked with taking personal care of the souls of children who died in infancy. One of her stories tells how, in her role as a pyschopomp, she'd travel the land with a breaking-down old wagon. Always accompanied by a crowd of little souls she needed to transport across a river to the land of the dead, where they would await their rebirth. In some versions it's a broken plough. When she finds a villager who is kind enough to help her, she rewards him by transforming the sawdust from the repair work into gold dust.

One of the rules that she had the job of enforcing was getting your housekeeping chores done properly and completely before a communal feast day. Having taught humans the art of spinning flax into linen, she took a personal interest in the crafts of spinning and weaving; leaving that work unfinished before the prescribed period of rest and recreation could result in her destroying what little you had gotten done, along with the any raw fibers left unspun. She wanted her people, particularly women, to be diligent in their work so that they would be able to participate in the community celebration, and not have to do chores while everyone else had a party.
It was said that at midwinter she'd lead favored women devotees in a Wild Hunt.

She was worshipped as a basically kind, benevolent mother goddess. A goddess who wanted her people to be both industrious and able to enjoy life. In modern terms, it could be said that she supported a sustainable work-life balance. Yet she also was someone you didn't want to piss off. Like most pagan deities, as long as you weren't lazy or just careless, she was easy enough to get along with. She actively encouraged her people to celebrate and strengthen their community ties. For the grieving mothers of babies who'd died, she was compassion itself. She would rain blessings down on the generous, and those who demonstrated their respect for her by maintaining their households properly. On cold winter nights people would leave offerings of food for her, seeking her blessing; a practice which persisted into the earliest times of Christianity in the region, and became part of the way that Christmas, especially Twelfth Night, was celebrated there. (Church authorities didn't like that much). For untold centuries she was worshipped as a Mother Goddess of might and purpose. A wonderful friend to those who loved her.
These days however, she has not just a fearsome reputation but a downright terrifying and gruesome one. Not to mention getting the most hideous makeover imaginable.
So what happened?

The Church. The Church happened.
We already know that the Christian church, as it spread across Europe and eventually the world, would rebrand and alter local pagan deities to suit their own purposes. Some were made over into Christian saints, keeping their original holy days, getting new stories, and adding "Saint" before their names.
Others were literally demonized. Which is what happened to Frau Perchta.
Beginning around the ninth century, the ecclesiastical propaganda machine shifted into high gear. This luminous, powerful Mother Goddess was eventually debased into a hateful, vengeful hag. The sometimes stern disciplinarian became a ruthless murderer. No longer content to just break your poorly spun thread, she'd slit your belly open, eviscerate you, then stuff that empty cavity with straw, rocks, dirt and broken glass before sewing you back up again. The kindly caretaker of little children's souls morphed into a demon who grabbed the souls of unbaptized babies and carted them off to Hell. (Really bratty kids could also get the belly stuffed with trash treatment). A grotesque old witch who flew around the sky riding on her distaff instead of a broom, in search of sinners to carry away to damnation.

Frau Perchta became a figure of terror used by the Church to keep people in line. But it may not have been as easy a transition as the Church authorities had hoped; apparently Martin Luther was still ranting about her cult in at least a dozen sermons centuries later. At any rate, by the 1400s the worship of Frau Perchta was explicitly banned by the Church.

These days she shows up in holiday parades alongside Krampus. Leering and grinning and dressed in rags. A beautiful and ancient goddess, scarcely recognizable now.
Thank you for reading. This is an open thread, all topics are welcome.