The crew of the PEN (Panther empire navy) Iocosa came close enough to be able to wrap their heads around the baffling idea of walling up a moon, but not close enough to fall for its deadly traps...

Even before they could make out the shapes of the many wrecks it had accumulated over the centuries, they knew it was made of pure evil. They never saw the city itself in its dark, decrepit splendor, let alone the infinity of chaos it was concealing. But just seeing the walls was more than they bargained for. What they were facing, could best be described as a gigantic, cosmic Venus fly trap, and it was slowly pulling the carcasses of ships into its thousands of hungry mouths...

They went to great extents to resist the fantastic feeling of greed and lust emanating from the cursed satellite, so that they could do their business and execute the maneuvers to get away from the sector. Two commanding officers had to be restrained.

On the way home, they realized to their dismay that the very premise of the mission, which consisted solely of scientific research, was obviously driven by the dark energy emanating from the satellite. The entire crew was to undergo psychological evaluation upon their return, but at least one crew member committed suicide before that was possible.

www.youtube.com/watch?v=oIBHwg…

Random advice to worldbuilders : when you write some lore, add a few loose strings. You can even put them in the mouth of a more or less well-informed character, so it doesn't matter if you change it or don't exploit it later on. I often do that, for instance here http://www.furaffinity.net/view/34524357/ there's a throwaway line about something I had no plan for; it planted the idea in my head and it developed into this. That's a way to make a world bigger and more complex overtime.