What happens is the opposite of what was expected or planned, in a way that reveals something about the characters or the world of the work.
In Don Quixote
this novella seems good to me, said the priest, but I cannot persuade myself that it is true; and if it is made up, the author made it poorly, for one cannot imagine a husband so foolish as to undertake such a costly experiment as Anselmo's. If this case were put between a suitor and a lady, it might pass, but between husband and wife there is something impossible about it.
The priest judges as implausible a husband who undertakes "such a costly experiment," right after he has witnessed a gentleman fighting wineskins, and the situation contradicts, without a word, the standard his sentence proposes.
Part One: The Curious Impertinent, the priest, at the end of the novella of the Curious Impertinent