One of the very best one I've seen back when I was working in the book publishing business (many moons ago) was this: a bogus screenshot (totally unrelated to t

One of the very best one I've seen back when I was working in the book publishing business (many moons ago) was this: a bogus screenshot (totally unrelated to the book) with a legend saying something like this: "Insert something similar to what's in book X at page 237"... With "book X" being the name of a book by a competitor. Somehow everybody (proofreader(s), author(s), etc.) ended missing that and the bogus screenshot and that legend made it to the final, printed, version of the book : )