I once read a short SF/F story on the blog of a Stack Exchange member, which I'd like to find again. (If you are the person with that blog, please do answer this question!)
It was basically a big joke about plot armour (warning: TVTropes link). There are several characters involved in a battle, bravely holding their own against vast numbers of enemy soldiers. It looks like they're going to be overwhelmed and slaughtered, but eventually one of them figures out (by examining the language used - their speech is always described by longer verbs than just "say") that they are the main characters in a badly-written short story. She deduces that they cannot possibly be killed, because of plot armour.
Then, their foes overwhelm them and cut their throats one by one.
It was definitely either science fiction or fantasy, and probably fantasy. I think the characters were using magic to shield themselves from the enemy soldiers, but it's possible they were actually using some sort of scientific plasma shield. The whole battle may have taken place in outer space, or at least up in the air, but I'm not sure about that part. I haven't managed to track it down by Googling - can anyone else find this story?