The Billion Year Bunker was a starship that was commissioned by the Galactic Government to carry certain "by-products", such as aorist rods and biological weapons. It was meant to be almost indestructible and the cargo hold had been reinforced in many different ways. The crew was to steer the ship towards a black hole, where it would be sucked in and forever be destroyed.
However, the captain took a detour to his home planet because he wanted some of the lobsters that were in abundance on the planet. The ship crashed into the water and split in two.
The Starship Billion Year Bunker appeared in Young Zaphod Plays it Safe.