The Sound of Drums (2) - S3-E12
Trivia: When the Doctor turns Martha's TV around to find the bomb, there's a sticker above it from Magpie Electricals, the TV shop from "The Idiot's Lantern." (00:14:25)
Trivia: Georgia Moffett, who stars as "Jenny" in this episode, is the real-life daughter of Peter Davison, the actor who portrayed the Doctor from 1982 to 1984. She married David Tennant a few years after this episode aired.
Trivia: At the undertaker's, the Doctor remarks on the strange behaviour of the gas light and Charles Dickens says "What the Shakespeare is going on?" This is a joke on Dickens' name, the expression "What the dickens...?" being a euphemism for "What the devil...?", making out that the phrase wasn't in use in Dickens' time and came from his name. In fact, "What the dickens...?" is much older than Dickens himself and has been in use since the sixteenth century, according to the Oxford English Dictionary.
Trivia: At the beginning of the scene where Clara persuades Rigsy to give her his chronolock, a poster can be seen on a wall in the background, reading "DeLorean" (a Back to the Future reference) in Aurebesh (the writing system from Star Wars). (00:25:00)
Trivia: Webley's empty Cyberman chess-playing machine, secretly operated by Porridge, who's hiding under the table, is a reference to a real 18th-century chess robot, the Mechanical Turk, which was operated using the same deception.
Trivia: When the Doctor sends the banknotes flying out into the street, all of the notes have David Tennant's or Phil Collinson's (the producer) faces on them, with quotes from the Fourth and Tenth Doctor (like "no second chances - I'm that sort of a man"). The notes have since become collector's items, selling often for about 50 pounds each.
Trivia: When Harriet Jones is explaining the sub-wave network to the Doctor's companions she says "It was created by the Mr. Copper Foundation." This is a reference to Mr. Copper from "Voyage of the Damned", who stayed to live on Earth and who probably would have had the advanced technology from the planet Stow where he came from.
Trivia: When everyone is walking through the hotel corridors shortly after the Doctor, Amy and Rory arrive, there is a brief scene where a PE teacher exits a room and starts berating the Doctor. Though never stated, it's implied that this is Rory's room. In The Doctor's Wife, when Amy and Rory are trapped on the TARDIS and are being taunted by House, he tells House that he had a PE teacher just like him.
Deep Breath - S8-E1
Trivia: In the scene at the end where Clara gets a phone call from the Eleventh Doctor, the shots with Matt Smith were filmed during the production of "The Time of the Doctor", almost a year before "Deep Breath" was made.
The Day of the Doctor - S7-E16
Trivia: The 2018 novelization, also written by Steven Moffat, includes a scene that he had wanted to include in the episode proper but couldn't due to rights issues, where UNIT head Kate Lethbridge-Stewart, while showing Clara around the Black Archive, shows her the posters of 1960s movies Dr. Who and the Daleks and Daleks Invasion Earth 2150 AD, which were loose adaptations of the first two Dalek serials, "The Daleks" and "The Dalek Invasion of Earth" starring Peter Cushing, and confirming them as existing in the Doctor Who universe. Kate then explains that the movies were made with the Doctor's knowledge, and that he was good friends with Cushing and loaned him a waistcoat to wear in the second movie. The novelization then goes on to add that the Doctor got in some trouble with UNIT for bringing Cushing to the future, to appear in a movie made long after his death - a nod to the late actor's controversial CGI resurrection in the Star Wars spinoff movie Rogue One.
Trivia: The 2018 novelization, also written by Russell T Davies, expands the scene where conspiracy theorist Clive shows Rose pictures of the Doctor in multiple time periods. In the episode, he only shows her pictures of Nine, but in the book, he has pictures of every incarnation of the Doctor up to Thirteen, as well as pictures of two incarnations from even further in the future. The two potential future incarnations are described as a "tall, bald black woman wielding a flaming sword" and a "girl or boy in a high-tech wheelchair accompanied by what appeared to be a robot dog". Conveniently, Rose happens to turn away just as Clive shows a picture of the Tenth Doctor, since she can't see him before the regeneration in "The Parting of the Ways". On a final, amusing note, the picture of Thirteen shows her being chased by a giant frog outside Buckingham Palace.
Trivia: There is a scene where several of the robot spiders are scrambling through ducts, and one of them bumps into the camera, despite the robots being CGI. This is a reference to a legendary blooper in the First Doctor serial "The Web Planet", where one of the Zarbi - large, ant-like aliens - bumped into the camera.
Deep Breath - S8-E1
Trivia: The Clockwork Droids that serve as the episode's villains came from the SS Marie Antoinette, a sister ship to the SS Madame de Pompadour from "The Girl in the Fireplace". It's not surprising that the Doctor finds the situation familiar. The fact that he doesn't recognize the name of the ship is also unsurprising - he never found out what the Madame de Pompadour was actually called in the previous episode.
Deep Breath - S8-E1
Trivia: The face that the Doctor wears when he disguises himself as a clockwork droid was cast from the statue of the Eleventh Doctor at the Doctor Who Experience. This is especially noticeable when he's pulling the face off.
The Time of the Doctor - S7-E17
Trivia: The external shots of the building where Clara's flat is located were shot at the same location used for some shots of the Powell Estate in "Rose".
Trivia: Lady Christina de Souza, one-shot companion for this episode, was based on ideas for the companion that would have succeeded Ace if the classic series had lasted to a season 27.
Chosen answer: No, no information is avalible for the identity of the entity.
Repo_Man