Superman

Superman was a fictional superhero that crash-landed on Earth as a baby, and was given the name Clark Kent. He was the last of his kind. Superman was the main character of a comic book series of the same name. (TV: The Return of Doctor Mysterio) He had a snow fortress. (PROSE: Dear Great Uncle Peter)

In one issue of a comic, he was faced up against Batman, and, as the cover promised, "only one can survive!" (PROSE: Curiosity)

In 1957, Korky Goldsmith claimed that Superman and Nyssa "would get along like a house on fire" as she was likewise the last survivor of her planet. (AUDIO: 1963: Fanfare for the Common Men)

The Twelfth Doctor read a Superman comic, and revealed to Grant Gordon that Superman and Clark Kent were the same person, making the point by drawing Clark Kent's glasses on Superman. When Grant told him that it was known by everyone (in the real world), the Doctor noted that Lois Lane did not know despite being a reporter. (TV: The Return of Doctor Mysterio)

Behind the scenes
As he revealed at the 2016 New York Comic Con, Superman, or more specifically Clark Kent, is Steven Moffat's favourite superhero. In writing the Ghost (Grant Gordon) in The Return of Doctor Mysterio, Moffat was particularly influenced by Clark Kent, and took inspiration from the Superman films of the 1970s and 1980s.

Superman appears as a character in LEGO Dimensions.

When Paul Kupperberg served as editor at DC Comics, he edited and sometimes wrote for Superman, among other titles, and also wrote for the newspaper strip of the same title.