Imagine, if you will, that a character does something despicable or foolish. Perhaps they were acting in an immoral way; perhaps they merely dared to rally against fate / the gods / the futility of existence / their own humanity. Whatever the reason, the universal kismet doesn't like it, so something totally unexpected but poetically just happens at the end to drive the lesson home, hard. Such endings are all but explicitly moralistic; it isn't enough for the universe to bring a situation to a just resolution, it has to resolve the situation in such a way as to both reveal what the moral of the story is and "demonstrate" the correctness of that lesson. This is a Karmic Twist Ending -- a Twist Ending designed to force An Aesop.