House (The Doctor's Wife)

House was a malevolent entity residing just outside the Universe which fed on TARDISes for their artron energy. It had servants it kept around for entertainment. House met its end when it tried to take over the Doctor's TARDIS, but was expelled by its matrix.

Biology
House was a malevolent, mysterious entity which lived in a small space outside of the universe. House existed as an intelligence in a space-time rift. His body was an asteroid-sized celestial object. At the time of his encounter with the Doctor, he implied that he was at least half a million years old.

The creature gorged himself on artron energy and at some point discovered the existence of the Time Lords, whose TARDISes were filled with just such a power source. He began using Gallifreyan distress signals to lure Time Lords to his surface, where they would be trapped. House would remove the TARDIS' matrix and devour the TARDIS. The trapped Time Lords would perish. When meeting the Doctor, House called the Time Lords a kind race.

The Doctor described House as "a sort of sea urchin", with a tough outer shell protecting a soft interior. This idea was raised when Uncle introduced the Doctor to House through a mesh-covered hole. House could possess other lifeforms. He used Auntie and Uncle to speak when he first met the Doctor, Rory and Amy. The green glow in the eyes of the Ood called Nephew was presumably also an indicator of House's direct telepathic influence.

House's energy was mostly green. When he controlled the TARDIS, its turquoise glass turned bright green, and green swirls went round the TARDIS.

History
Uncle, Auntie, the Ood Nephew and Idris came upon House and lived on his surface. As Time Lords died there, he renewed the bodies of his servants and replaced parts of their dying bodies with dead Gallifreyans who had also stumbled upon House. His servants became an extension of his will and carried out his every wish. After the near-annihilation of the Time Lords in the Last Great Time War, House grew hungry and attracted the attention of the Eleventh Doctor, who was accompanied by Amy Pond and Rory Williams. House sent a psychic distress signal box, originally broadcast by a Time Lord called the Corsair, into their universe through the rift.

House used his powers to remove the Doctor's TARDIS' matrix and put it into the body of Idris, leaving it blank for him to consume. However, during a conversation with the Doctor, House learnt the Time Lords had perished in a terrible conflict. Realising its food source had been eliminated, House decided to change its behaviour by possessing the now empty TARDIS and using it to reach the main universe to find new sources of energy. The Doctor found the cache of hypercubes sent by the dead Time Lords House had trapped. The Doctor and Idris built a TARDIS from the scraps of old TARDISes about the asteroid to pursue House.

To amuse itself, House used the TARDIS to play with the minds of Amy and Rory. However, the Doctor caught up with House. The TARDIS matrix was released from her dying human body, allowing her to repossess the time ship. House's essence was expunged from the ship, the Doctor mockingly informing House that where the TARDIS was bigger on the inside, House was "just so small" even when physically the size of a planet. (TV: The Doctor's Wife)

Personality
House had a sadistic and evil personality. It took pride in the fact that it had killed hundreds of Time Lords and enjoyed watching its victims suffer. Rory and Amy managed to use this trait to buy them more time since House had considered just killing them straight away but decided to amuse itself first after being pursuaded by Rory. House was shown to be arrogant, telling the Doctor to fear it since it had killed many Time Lords and being confident that it could kill him easily. However it showed anger and even fear when the TARDIS returned to her rightful home and was defeated by the TARDIS matrix. (TV: The Doctor's Wife)

Behind the scenes

 * Writer Neil Gaiman said in an interview in Doctor Who Magazine #448 that earlier drafts of The Doctor's Wife implied that House was actually the Great Intelligence. These hints did not make it into the episode as aired. The Great Intelligence would return to Doctor Who in series 7's The Snowmen.
 * After the airing of The Doctor's Wife it was noted that its storyline had a lot in common with the comic story, Nineveh!. House's counterpart is the Watcher of Nineveh, a similar incorporeal entity which murdered many Time Lords and was able to penetrate TARDISes, resulting in a TARDIS junkyard.
 * Eleven Things You Probably Didn't Know About the Corsair explained that the Ninth Corsair came across House as part of the Time Lords' Fourth Universal Survey Expedition.