Jack Frost is a big blue man who is seen in "Eye of the Beholder". He is seen as one of the judges. He asked Fu what would his favorite weather be. Fu said answered saying it was winter which is Jack's favorite season.
Jack Frost: "What would be your favorite weather be?"
Fu: "Ummm... Winter?"
Jack Frost: "That's more like it."
Jack Frost is based on the personification of frost and winter.