Hippopotamus

Hippopotami, or simply hippos, were large, Earth-native mammals who spent the bulk of their time in mud or bodies of fresh water. The Second Doctor and Jamie once used a herd of animals — which included hippopotami — to stampede a group of Quarks. (COMIC: Jungle of Doom)

The Sixth Doctor once complained to a television station because, amongst other programming deficiencies, they allowed a blue hippo to be a newsreader. (AUDIO: The Ratings War)