The TARDIS once materialized on a swampy planet for the Second Doctor, John Who, and Gillian Who to test out the Doctor's "Bug."
The planet was covered with large bubbling mud pools surrounded by patches of steaming jungle, the Doctor considering it an ideal testing ground. The Grand Witch held a meeting of the Witches there when she created a host of man-eating bats to fly through space and savage Earth, but using the Bug, the Doctor scared the Grand Witch into reversing her spell by claiming to be more powerful "swamp demons." (COMIC: Return of the Witches)