Making his way to the ship's control room, the Doctor finds it automated, abducting children to harvest their creativity and upgrade the Pathweb. Suspecting that the old ship was pulled out of storage for the Last Great Time War, the Doctor wires himself in and puts it in a holding pattern, stripping its software to its most basic levels.
Despite this however, the door remains locked, even to the Doctor's Dalek impression. After Emily mentions "basic functions", the Doctor realises that the most basic thing to a Dalek is "Kaled", the word opening the door.
After gifting the ship to the people, the Doctor explains anagrams to Bill, using the example of "Eleven plus two" and "twelve plus one", both of which add up to thirteen.
Because of the ubiquity of this race, no attempt will be made here to list every appearance in every medium. Instead, we focus on comic appearances here, and invite you to explore a complete list of appearances elsewhere.