This reminds me of a movie from the early 90s called Crazy People. An ad exec has a nervous breakdown and ends up in an institution. He accidentally sends off truthful ads that he and the other patients write, they get produced, and they are very successful. It was a pretty funny movie. Some examples of the campaigns
"Metamucil: It helps you go to the toilet. If you don't use it, you'll get cancer and die."
"You may think phone service stinks since deregulation, but don't mess with us, because we're all you've got. In fact, if we fold, you'll have no damn phones. AT&T - we're tired of taking your crap!"
"Paramount Pictures presents 'The Freak.' This movie won't just scare you, it will fuck you up for life."
"Porsche. It's a little too small to get laid IN, but you get laid the minute you get out!"
"Volvos, Yes they are boxy, but they're safe".