Planet of the Spiders

Planet of the Spiders was a serial of Doctor Who that aired prior to 1981. The serial depicted the regeneration of the Third Doctor into the Fourth Doctor, and the serial was later novelised as a book of the same name. (PROSE: Fanboys)

Behind the scenes
This is a version of Planet of the Spiders that exists within the Doctor's universe.

The eleventh season of Doctor Who does also exist within the Doctor's universe, however there is no mention of this serial being part of this season by a valid source, despite their real world connection.