Worm

Donna Noble compared Time Lords to worms after witnessing the severed hand of the Tenth Doctor grow into a new Doctor. (TV: Journey's End)

Two phlya of worm were anelida and nematoda. The Doctor thought the Laan may have been members of these phyla. (AUDIO: The Sands of Life)

There was once a worm next to the Doctor's picnic basket when he sat down outside the TARDIS. (COMIC: Enlightenment)