The Invincible (in original: Niezwyciężony) is a science fiction novel written by Stanisław Lem and published in Polish in 1964. The translation into German was published in 1967. The English translation of the German translation was published in 1973.

A spacecraft, called Invincible for its high military potential, lands on a planet to investigate the loss of another spacecraft, of an identical model. During the investigation, the crew finds evidence of a new form of life, born through evolution of autonomous, self-replicating machines. The evolution was controlled by "robot wars ", and the only survived form was swarms of minuscule machines -- a foresight of nanobots. When bothered, they assemble in huge swarms to defeat an intruder by what could have been called today -- a powerful surge of EMI. Some members of the spacecraft crew suffered a complete memory wipe-out. The angered crew attempts to fight the enemy, but eventually recognizes the meaninglessness of their efforts in the most direct sense of the word.

The novel turns into an analysis of the relationship between different life domains, and their place in the universe. In particular, it is an imaginary experiment to demonstrate that evolution may not necessarily lead to the domination of superior life forms.