Excroth

Excroth was the "favourite planet" of the Ninth Doctor. He took Rose Tyler and Jack Harkness there, but found that the planet had been destroyed. At the time they arrived, the Doctor said should have been the middle of the Second Excrothian Tetrachy, a period of unparalleled scientific enlightenment. The Doctor found that the planet had been destroyed by the Lect, who had a ship in the Excroth system. (COMIC: Weapons of Past Destruction)