Just for fun, a background description + download for giant worm to burrow through planets
The Ferro Mortem, also known as the steel worm, is a massive space borne predator, capable of destroying entire planetoids with their burrowing. It is undoubtedly mechanical, but acts with its own feral intelligence, and has been seen in various forms, sizes, and lengths. Many theories exist for its creation, most common of which is that all specimens of these worms are rogue drones from some unknown factory, now spread throughout the cosmos without discernible purpose.
Ferro Mortem.drn