The singularity is a sci-fi end-of-days story. It speculates that at some point we'll invent an AI that's about as smart as a human, and smart enough to design a better version of itself.

Then a week later it'll come up with a version of itself that's twice as smart. A week later that version will come up with a version that's twice as smart again, making it 4x as smart as a human. A week after that, it'll come up with a version that's twice as smart again, 8x as smart as a human. And so on. A year later it'll be a trillion times smarter than a human.

The AI will then either solve all our problems, invent fusion power and faster-than-light travel, and usher in a Star Trek style post-scarcity world of infinite resources and luxury, or it'll take over and create a Terminator style oppressive dystopia where the few surviving humans survive on rats we roast over a barrel in our underground bunker.