Vwoorpy
The vwoorpy was the name given by Alice Obiefune to the signature sound made by the TARDIS dematerialisation circuit. (COMIC: The Then and the Now) It was alternatively refered to by Cindy Wu as the sexy elephant noise and the elephant-and-ancient-piano-dance sound (COMIC: Old Girl) Ace compared the noise to the sound of a key scraping a wire. (PROSE: Head Games)
Having required a recording of the Doctor's TARDIS dematerialising, Victor Kennedy played it to LINDA, describing it as the "sound of the universe". Elton Pope, who first heard the sound as a child when the Tenth Doctor came to his home, believed it to be the "most beautiful sound in the world." (TV: Love & Monsters)
Observing a reaction in the Tenth Doctor's hand, Captain Jack Harkness realized that the Doctor had returned to Cardiff as the TARDIS' materialisation sounded, promptly leaving the Hub to intercept him. (TV: End of Days, Utopia)
The Eleventh Doctor voiced that he loved the noise, describing it as "brilliant". To his confusion, the sound, which he imitated by breathing heavily, was not heard when River Song piloted the TARDIS. River claimed that the TARDIS was not supposed to make that noise which was a result of the Doctor "leav[ing] the brakes on." (TV: The Time of Angels)
The consciousness of the Doctor's TARDIS, when briefly transposed into the body of the humanoid Idris, performed a perfect vocal replication of the sound in order to identify herself to the Doctor. The noise was also heard when the TARDIS consciousness was transferred to and from Idris' body. (TV: The Doctor's Wife)
Taking the TARDIS to the source of the mysterious message beamed from Trenzalore, the Doctor turned the engines "on silent" in order to avoid "mak[ing] a fuss." (TV: The Time of the Doctor)
