The Monster

The Monster - unstoppable ancient robot beast built by Humans, which goal was to entirelly destroy the planet of Argens in Lem's novel Cyberiada. His size was so huge that his spin, seen from far, looked like mountain range.

Origin
Detailed origin of the Monster isn't known, but it was surely build by humans, named by robots Palers.

History
The Monster was awaken during the lordship of king Inhiston. The Monster was annihilating everything that it saw. Nobody on the entire planet didn't know where the Monster came from, but some people claimed that it's undead creature. However, they weren't completely wrong, because after every killing of Monster (which appeared to be almost impossible) it just ressurected and started its terror again.