Zog (planet)

"Zog" was a colloquialism Donna Noble once employed to indicate to the Tenth Doctor that she was referring to "a hypothetical planet". (TV: The Unicorn and the Wasp)

There was, however, an actual planet named Zog. Captain Jack Harkness once visited a bar on the planet on New Year's Eve 2066. There, an individual of an unnamed species gave him instructions for the either earlier or later version of him. This version, upon opening a box on 7 August 1941, relived these experiences. (COMIC: Overture)

Behind the scenes
Zog (Planète)
 * The colloquialism likely derives from Zig and Zag, puppets famous in the British Isles, who were said to come from the planet Zog.
 * In The End of Time, Jack visits an unnamed bar in an unnamed city on an unnamed planet. Though the episode as televised leaves the audience clueless as to the identity of these places, the script and online commentary were more forthcoming. Between these two out-of-universe sources, writer Russell T Davies specified the planet as "Zog", the bar as the "Zaggit Zagoo bar" and the city as "Zaggit Zagoo".
 * The Zog bar is a possible reference to the Zaggit Zagoo bar, and may be intended to be one and the same.