The Antrozenus Zone was an isolated area of space which was normally quite empty. The Eleventh Doctor once parked his TARDIS in the zone to get some time to talk to the Sapling, but was surprised to find a Xerxes Memory Ark infested with Thrake which had drifted into the area. The Doctor, the Sapling, and Alice Obiefune boarded the Ark and dealt with the Thrake. (COMIC: The Memory Feast)