Her name shares the same root as the word "bright". Also "birch", a tree she's associated with. She also related to the myths of the Weisse Frauen ("White Ladies"), elven spirits in female form who would appear to mortals (and inspire both The Professor's Galadriel and Eowyn (after she married Faramir and moved with him and his rangers to Ithilien </GEEK>)

Some myths have Perchta (or her male aspect Berchtold) as the leader of the Wild Hunt. The Belly-Slitter is associated with animals, spinning, and fiber-crafts, and she not only blesses the shepherds and their flocks, girls/women spinning yarn during the holidays risk Perchta's knife. This is because they were lazy and didn't get their work done on time. Some versions have her boiling her victims like a skein of yarn.

Also, people who don't feast enough during the holidays were considered to be not invoking enough good mojo for the community during the darkest, most liminal time of the year, and thus were also at risk. A full stomach is said to be proof against the Belly-Slitter's wrath. (Intestines on the floor she can handle, but I guess a big, wet mass of undigested holiday meal in a beer soup is gross.)

Some myths depict Perchta as ugly, with a long nose, while in Slovenia, she is a tall, beautiful valkyrie-like figure. Perchta is attended by the spirits of children who died unbaptized known as perchten. They, like their mistress can be either Schönperchten ("beautiful") and bestow luck and blessings, or Schiachperchten ("ugly") and drive out demons and ghosts when they come. (I could be wrong on this, but it's my understanding that the masks that have horns are traditionally Krampus (Dec. 5th), and that those without are perchten (Jan. 5th). But these days, everyone brings out all their masks during the holidays, leading to some confusion.)

So, don't be lazy, get your work done on time, party hearty... and you might just survive the holidays.