I read a story on reddit about a home health aid that was taking care of an elderly man with a very swollen growth on his face. It got to the point where he could no longer see out of his eyes, but he was so old and frail that doctors would not operate. One day he was in the bathroom and the whole growth fell off into the sink. It had become infested with maggots. What ended up in the sink was a writhing mass of disgusting rotten flesh, but what was left on the man's face was new, pink skin. The maggots had saved his eyesight.

I'm paraphrasing here but I thought that was a cool story.