Adipose 3
Adipose 3, also known as Breeding Planet One, was the planet used by the Adipose or, more specifically, the Adiposian First Family, to breed their young, before being taken home by the wet nurse that took care of them.
At some point before 2009, the planet was stolen by the New Dalek Empire and transported to the Medusa Cascade. (TV: The Stolen Earth)
Faced with its disappearance, the first family decided, in violation of Galactic Law, to select Earth as a new breeding planet because of the number of obese humans. (TV: Partners in Crime)
In the Medusa Cascade, Adipose 3 and twenty-six other planets formed the engine of a reality bomb with which the New Dalek Empire planned to destroy every universe. It was returned by the Meta-Crisis Tenth Doctor to its proper place in space and time after the Daleks were thwarted. (TV: Journey's End)