For me the freakish thing was having GPT-4 complete the prefix of a script, which was mostly a doc-comment and the inputs, written in my style. The completed body of the script was also in my style, even though I had not given GPT any actual "code" in the prompt. It somehow had learned that people that write the preamble "just so" also write script logic in a certain specific way, and it could emulate that.