79B Aickman Road

The apartment at Number 79B, Aickman Road was in reality a timeship of unknown origin that came to Earth at some point prior to 2010.

Characteristics
From outside, Number 79B was somewhat like an inverted, curved pyramid, with four legs/landing struts. It was capable of using a perception filter to give it the ability to blend in with its surroundings and convince anyone who looked upon it that it had always been there. When it took on the appearance of the non-existent upper floor of 79 Aickman Road, even Craig Owens, who actually lived in the house, accepted the sudden appearance of a second story. The Doctor, after first seeing the ship, called it "someone's attempt to build a TARDIS". While he may have meant that the ship was made to be a time machine rather than a TARDIS specifically, the ship did hold a dark resemblance to one, based on the layout of the room as well as a device that looked strikingly like a time rotor.

The ship apparently drew some kind of power from its pilots, who steered the ship with their thoughts. Although it is unknown what species originally piloted the ship, humans were incompatible; the energy-drawing process invariably resulted in the would-be pilot's death.

The ship had a holographic autopilot which activated when damaged. The autopilot searched for people to power the ship, using the intercom to communicate with people outside the building and changing its appearance to lure them in. All of the holograms seemed to lure the victims by saying that they needed help. (DW: The Lodger)

History
Number 79B, Aickman Road was a timeship that had crash-landed on Earth sometime before 2010, killing all of its crew. The ship disguised itself by pretending to be the upper story of 79 Aickman Road, a flat owned by Craig Owens.

The ship's autopilot attempted to relaunch the ship using Humans as pilots, specifically selecting humans who wanted to escape or explore. However, the mind of a human was too weak to launch the ship, and so the people selected by the autopilot were killed. This also created a decaying pattern on the ceiling below, much like rot in appearance. The autopilot's attempt to launch the ship with Humans also caused a time loop to form briefly, almost resulting in the TARDIS and Amy being thrown into the Time Vortex.

The Auto Pilot later attempted to use the Doctor's mind to launch the ship, but the Doctor claimed that his mind would be too much for the ship. Craig Owens was able to shut down the ship because he didn't want to escape or explore; he wanted the opposite. The ship imploded when the emergency shutdown was activated by Craig. (DW: The Lodger)

Behind the scenes

 * Doctor Who Adventures magazine released a post for The Lodger stating that the enemies in the episode were dubbed "The Avatars".