The figure of Jack Frost appears in the dream.
He is a figure from English folklore, and there are similar figures in German popular belief.
There is St. Nicholas, the icily gray and cold one; he is the old man symbolizing the beginning of winter.
St. Nicholas, however, is a benevolent figure. Why?
Participant: He’s like the Erinyes, who are evil and benevolent at the same time.
Professor Jung: Yes, often a good name stands for an evil cause.
Participant: St. Nicholas is also split into two figures. He usually is accompanied by Knecht Ruprecht, who represents the devil. He comes with a rod and a sack, in which there are the children he has already taken.
Professor Jung: Where does he carry the bad children?
Participant: Into the forest.
Professor Jung: Yes, into the forest. And what happens there? What is the forest?
Participant: It is a dark place, full of dangers.
You know the saying “To hell with him!”
This means that the devil takes you to the place of darkness and terror, actually to the place of the dead.
St. Nicholas, too, takes the children to the place of darkness.
As the gray one, who appears at the beginning of December, he is also death, who takes man into the world beyond.
He is a kind of judge of the dead, who punishes the bad and rewards the good, similar to Osiris, the judge of the underworld.
So a very serious meaning is concealed behind the figure of St. Nicholas.
Jack Frost corresponds to St. Nicholas, although he is much less incorporated into folkloric culture.
He, too, appears at the beginning of winter and represents coldness, which implies a memento mori.
A white ghost, he seems to be covered by the shroud of snow. ~Carl Jung, Children’s Dreams Seminar, Pages 340-341.