Grýla
Grýla is the monstrous ogress of Icelandic folklore who descends from her mountain cave (Dimmuborgir) at Christmas to hunt naughty children, stuffing them in her sack. Mother of the thirteen Yule Lads, wife of Leppalúði. Documented since the 13th century (Svarfdæla saga) and in Jón Árnason's collections. Originally a generic troll-woman, later specialized as a Christmas disciplinary figure.