system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The allegorical meaning of Stanley Kubrick's "2001: A Space Odyssey"
gpt
The monolith is an evolution stone.  Think of it like giving a thunderstone to Pikachu.

Every time humanity manages to encounter it, we have levelled up to the point where we are ready to evolve.  The first evolution was to use tools, leaving savagery behind.  The next time was to become space dwellers, leaving the planet behind.  The third and final time was to step outside ourselves, leaving behind our physical form.

Therefore, the allegory in the movie is (ironically) that the constant, unchanging black monolith represents change.  Change is inevitable.