Celestial Omnibus

Iris Wildthyme's TARDIS, known as the Celestial Omnibus, resembled a red London double-decker bus, specifically the Number 22 to Putney Common.

Unlike other TARDISes, it was slightly smaller on the inside than on the outside. (PROSE: The Scarlet Empress) According to one account, the bus was not actually smaller than other TARDISes, but instead most of its interior dimensions were used to store water. (PROSE: Verdigris) However, Panda once said that the bus got its water from a space-time link to a Canadian lake in 1924. (PROSE: Enter Wildthyme)

The inside looked like a modified double-decker bus, though with a few hints of its true nature. (PROSE: Old Flames) The TARDIS had a small kitchenette in the back, a shower and a wardrobe upstairs. The controls were on the dashboard. The controls resembled those of the Doctor's TARDIS during his eighth incarnation. (PROSE: The Scarlet Empress)

The lower floor of the bus contained a record player and a rack of records, including some by Tammy Wynette. (PROSE: Future Legend) Iris also had a collection of tapes, including a Geoff Love rendition of the Doctor Who theme, Shirley Bassey singing What Now, My Love?. (PROSE: Bafflement and Devotion) and several Vince Cosmos songs. (PROSE: Enter Wildthyme) There was also a drinks cabinet. (PROSE: Old Flames)

History
Iris found the bus during her youth in the Obverse, where it had crashed, and breathed new life into it. She then left the Obverse in the bus into the universe beyond. (PROSE: Wildthyme Beyond!)

Iris once had Christmas dinner with Fifth Doctor, Tegan Jovanka, and Vislor Turlough in the bus. (PROSE: The Scarlet Empress)

When the Obverse was altered to be a bit more steampunk, the omnibus was transformed into an airship. (PROSE: Flasket Brinner and the Clockwork Heart et al) On one occasion, a member of Faction Paradox fused Panda with the airship. (PROSE: Panda and the Airship)

In a possible future, Iris had changed into Bianca — Iris' own version of the Valeyard. Bianca converted her breaking-down TARDIS into a nightclub, planning to snare Iris and take her remaining regenerations. The Sixth Doctor used his own TARDIS as a time ram to destroy the club. (AUDIO: The Wormery)