I believe I just deleted the first secretly ChatGPT-generated comment on the forum for an OSS project I maintain. It was shaped like an answer, but didn't actually answer the question. Great grammar, sounded authoritative. But, wrong. The internet is absolutely going to become gray goo, and it's going to happen so fast.
@swelljoe you've described 9 out 10 comments I come across without this latest chat bot.

@craige no, the grammar was excellent.

Jokes aside, I think that's one of the reasons it's so dangerous. Humans are suckers for a confident liar (it's "con man" for a reason), and ChatGPT is so confident and so authoritative sounding. It's exactly the kind of answer we want, but fictional. If a dumb human makes a suggestion, there are probably cues that allow us to judge their value. Many of those cues are distorted or gone. I can mostly detect LLMs for now...but soon, I dunno.