Whilst I don’t really disagree with the other answers, I think it’s unfair for nobody to give the pro-singularity argument, so here it is.
We have reason to think that humans are a minimum viable general intelligence, like we evolved just enough to cross that rubicon, then evolution stopped mattering much because we started developing faster than it could keep up, and the difference between first proper intelligence and us is basically minor fiddling from an evolutionary perspective.
meanwhile our brains are a complicated mess that we barely understand and can’t improve upon. Or at least we’re not smart enough to improve it atm.
An agi will probably have a much more iterable brain (if nothing else they’ll be able to change some settings and see what happens, which we can’t really do either ethically or quickly.
Finally, it doesn’t really make sense to talk about an agi of human intelligence, because our intelligence is defined by some rather ridiculous limitations that no agi will ever have, so the first “human level” agi will be vastly better than us at some things (hell, even before LLMs computers were superhuman at lots of stuff).
Combine all that together, and you can imagine a scenario where the first proper agi is also so much better at designing agi than we are that it very quickly rebuilds itself into something even more beyond us. End result is it surpasses us faster than we can react, I think the name is meant to evoke the concept that there’s no way to see past the event horizon, once we’ve built it everything is different in ways we cannot predict.
As I said, I don’t actually think this is likely, but you deserved a nuanced answer not just everyone joking about it.



I have just invented a radical new form of free speech, I’ll call it pure free speech.
In pure free speech, you’re free to say anything to anyone without having any consequences whatsoever.
This is achieved by everyone agreeing to not respond to speech in any way.
Someone shouts fire in a cinema? that’s fine, it’s their choice, nobody listen.
Somebody asked you for the time? That’s fine, it’s their choice, don’t respond in any way.