The Snowman

The Snowman was a television special that was repeated on Earth around Christmas. It featured a snowman that flew around, and danced with Father Christmas.

Mason Valentin grew bored over how often it was repeated, while the Tenth Doctor loved it. When the Doctor said goodbye to Mason, he said, "after all the flying around, having fun, and doing the impossible I've reali[s]ed something: I'm the Snowman and...time's up." (PROSE: The Doctor on My Shoulder)