Planet made of toothpaste

From Tardis Wiki, the free Doctor Who reference

A planet made of toothpaste was once visited by Scandrius and Tegan Jovanka when Scandrius stole her and a TARDIS to escape Gallifrey and explore the universe, fighting evil. With uneven terrain and a constant minty smell, Tegan told Scandrius she thought the planet was made of toothpaste, although he didn't know what it was. (AUDIO: Time in Office)