Rock-bugs are a species of tiny insectoid beings which exist in huge numbers in a small rock fragment orbiting Saturn, amidst the planet's ring system. Despite looking like non-sapient organisms, they're actually not only intelligent, but also have a keen affinity for solving mathematical games and puzzles.
The Rock-bugs exist in numerous aggregations and feed upon anything of metal. They're known to infest metallic structures (up to and including spaceships) to lay eggs in them, which hatch within a period of a few weeks. While they're attracted to metal, they typically show an aversion to wood, which is an entirely unfamiliar material to them.
Because they exist only in one specific rock among many, it has been speculated that said rock may have originated elsewhere, perhaps from another star system, and drifted through space before being captured by Saturn's gravitational pull.
- "Mr. Meek Plays Polo", by Clifford D. Simak (1944)