Zygon spaceship

Zygon spaceships bore a strong resemblance to crabs or barnacles, and their overall organic appearance suggests that they were grown rather than made. Many of these ships roamed the universe after the destruction of Zygor in a stellar explosion. (PROSE: Doctor Who and the Loch Ness Monster)

The Doctor claimed that there was a Zygon spaceship beneath the Savoy Hotel. (TV: The Power of Three)