Zygon spaceship

Zygon spaceships bore a strong resemblance to crabs or barnacles, and their overall organic appearance suggested 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)

History
On 26 June 1890, the Eleventh Doctor found that there was a Zygon spaceship beneath the Savoy Hotel, half the staff of which were impostors, when he took Amy Pond and Rory Williams to the hotel. Ultimately, the Doctor saw the the situation was "fixed". (TV: The Power of Three)