The Planet Eater

Mon*Star describes it as a living force under a pile of dead rockets whose one purpose is to make more fuel than it is given. That is a breeder reactor, and it is a startlingly specific piece of physics for a 1986 cartoon to reach for.

It had eaten ten freighters by the time Stargazer briefed the squadron on it. The surface looks like scrap metal and junk. The inside is lit like a furnace.

The Steel twins blow it and everyone moves on. It survives, and returns in a plot to replace the Artificial Sun. It has a locations entry as well, because the show treats it as a place as often as a machine.