Boa constrictor

A boa constrictor was a type of snake. They preyed on rabbits and ate them whole. (TV: The Time Monster)

The Fourth Doctor, after being told the history of the Meeps, said that Beep was "as gentle as a boa constrictor". (COMIC: The Star Beast)

In circa 10,000,000, boa constrictors were among the animals on board the Ark. One of them attacked a Guardian, but he was rescued by a Monoid. (PROSE: The Ark)