Flubble

The Flubble is a type of creature somewhat like a koala with six legs and a smaller nose. The Doctor had a pet flubble under his bed while he was still in the Academy, though he was nearly caught when she came into heat and starting using its mating call. (PDA: Island of Death)


 * Since the Doctor was still in the Academy, it would suggest the flubble is native to Gallifrey. Of course, due to the Time Lord's abilities, they could potentially get creatures from any point in time or space.