Ignore the title of the blog itself (“Funny AI Fails”). I confirmed with the author that he wasn't kidding:

* He gave ChatGPT a single 300-word prompt describing an open problem in his area of expertise, game theory, and asked it to write a complete paper

* It thought for 90 minutes and wrote the paper without any guidance

* “If this had been an advanced undergraduate doing a semester-long independent study, I imagine it would have very easily been an A and I would have encouraged the student to work on it just a bit more to submit it for publication somewhere.”