There's far better examples, but atm there's one specific title that really sticks out in my mind.
I don't read much
It's called The Hotel New Hampshire. Based on the description I read, I was expecting long paragraphs abput curling up next to a fireplace in the middle of New England blizzards and a family's struggle to run a hotel and stay together.
Instead, I got bears, lesbians, incest, a boy named Egg, terrorists, and the main character disposes of the bad guys in a way that I don't think is possible in real life (not gonna spoil it in case somebody actually wants to seek out and read this thing for themselves).
It wasn't a bad book, really. Just so radically different from what I thought it would be that it threw me off.