Plungboll

Plungbolls are tiny, fur-covered organisms approximately the size of Sarah Jane Smith's thumbnail. They are native to the snowy mountains of Gallifrey.

Plungbolls attach themselves to any source of warmth that happens by. Some travelers have suffocated to death, covered with thousands of the creatures. To avoid this fate, a chemical called anti-plungboll spray has been developed; this substance causes them to drop off of their would-be victims, squeaking. (AUDIO: The Ghosts of N-Space)

Behind the scenes

Plungbolls were mentioned in Doctor Who Insider #3.