The Lady of the Cold
Once a year, every winter, The Lady of the Cold makes an appearance in Moominvalley. Out of fear, most creatures stay away when she arrives, except for those who forget she is on her way. When you look into the eyes of the Lady of the Cold, you freeze and turn into ice.
Tove Jansson never drew the Lady of the Cold, but she is described as an incredibly beautiful woman, white as the snow and with cold, blue eyes.