Planet (The Not-So-Sinister Sponge)

The Fourth Doctor, Romana, and K9 once visited an uninhabited planet made entirely of confectionery. When Romana noticed K9's bad mood, she realised they had forgotten his birthday, and travelled to Kendrax to fetch him a cake. When she returned with the Cake, it came to life and asked politely not to be eaten. The Doctor theorised that the unique combination of a trip in the TARDIS, exposure to the telepathic circuits, and the unusual properties of the confectionery planet brought the Cake to life. At K9's suggestion, they released the Cake into the wild, where it could live out its life on the confectionery planet. (PROSE: Special Occasions: 1. The Not-So-Sinister Sponge)