The Snowman Priest appears in "When Wedding Bells Thaw." He appears to hold some position of power in the Ice Kingdom beneath the Ice King, conducting the ceremony and advising the Ice King during his wedding. He may be something of a clergyman or bookkeeper, remembering and recording rules and laws for the Ice King. He is one of the only snowmen in the Ice Kingdom. He appears again in Legends of Ooo at the end of the game.
He looks like a regular snowman, but he has three eyes and is wearing a carrot on his head. He also is seen holding a piece of paper.
Yes, it's official.