Phylox series
From Tardis Wiki, the free Doctor Who reference
The Phylox series was, according to the TARDIS Index File, the location of the planet on which the city of Castrovalva was located.
Exactly what was meant by the word series in an astronomical context was unknown, particularly because the Index File noted that "Castrovalva [was] the central habitation of the planet that forms the Phylox series". This begged the unanswered question of how a single object made a series.
However, because the Master (Tremas) instructed Adric to place the false entry into the Index File, nothing about the information was true. The Phylox series likely never existed. (DW: Castrovalva)
