Gryla is sometimes referred to as a giantess, which may be an attempt to soften her image. her description in most tellings of the legend is pretty scary. She is described as having hooves for feet and thirteen tails. She has the face of a woman, but is very ugly. She lives in the mountains and at Christmas she comes to town to get all the bad children.
She was not originally associated with Christmas. She first came on the scene in ancient Pagan times, but by the 17th century she was part of the visiting tales told at Christmas. Her name is thought to mean threatening and she certainly is that. She doesn't come to town bearing rocks for gifts and other such unpleasantries. She comes to gather the bad children and when she gets them, she puts them in her sack and takes them back to her cave. And while other Christmas baddies like to whip and beat children, Gryla likes to eat them. She typically boils them alive to make her favorite stew. She places them in a sack and drags them back to her cave where she boils them alive for her favorite stew.
Adults aren't safe either, especially if you are a man and happen to marry this catch of the Icelandic mountains. She's already killed three husbands. Maybe you might like to be hubby number four? Apparently she made some babies with these men. The thirteen Yule Lads are said to be her sons. And as we already know, they add to all the Christmas nightmare fun!