The Transient Planet is among the most impressive single works of the Xeroteais race. No one, not even the remnant element of that race, knows where the original core planet was taken from, only that it was a lifeless world taken from a remote star system by a mind boggling business venture.
The first step of that business venture was awe inspiring, but not quite completely crazy. The barren, lifeless world was sub-divided into a roughly one hundred and twenty sections, and in each section was installed an immense underground infrastructure that terraformed each section into a unique version of paradise. This, the creation of an entire resort world, where personal paradises could be rented out by anyone with sufficient wealth, was an incredibly ambitious idea for a single business, but not quite into that extra level of ridiculous that the Xeroteais have become known for.
The second phase of their design more than made the leap.
Rather than being content with the manufacturer of an entire resort world, the Transient Planet's designers decided to make the planet capable of moving. That is to say, they made the entire planet capable of super-luminal travel. Once they had accomplished this insane and impressive feat by securing the planet with shielding and installing the largest FTL drive ever made, they proceeded to create a "tour" of the galaxy with the planet at its core. The planet would jump from solar system to solar system along a route calculated to show the visitors on the planet the most impressive possible vistas, completing a circuit of the designed route every 7 years. The planet was not particularly fast by Xeroteais standards, so tourists would take a fast passenger liner (one of the fastest ships the race ever managed to create, just to add to the ridiculousness of the project) to the planet's current location and enjoy their selected variation of paradise until their vacation was over.
As with many of the wonders of the Xeroteais, the Transient Planet was abandoned when a plague they couldn't cure swept through their section of the galaxy. The small remnant of the race that survived the plague lost so many of its people that it has not been able to muster the manpower to move much beyond the races' home system.
While they have managed to retain most of their technology, the extremely low birthrate of the species has prevented them from recovering enough population to supply their large projects of old. When they discovered another race had managed to make use of the Transient Planet, as well as a number of their other pieces of technology, they were delighted rather than distressed.
As it was explained to the expedition that found them, the Xeroteais culture has a strong dislike for letting their technological marvels go unused. As such, they formally leased the use of the planet to Fredrick Saint Claire and his expedition, in exchange asking only for basic information on areas of the galaxy they had never traveled to and races they had yet to meet. Sadly, they were unable to explain how its drive technology worked, as it had been a corporate secret of the group that built it, and said company had been wiped out during the plague.