I am subscribed to a Word of the Day service. I have a decent vocabulary so I'm familiar with many of the words. But this was a new one to me!! Adynaton. (a-dih-NAH-ten) Latin, mid 17th century A figure of speech by which an impossible (or highly unlikely) situation is used for emphasis. An instance of this. "With a bit of adynaton, the story went from mundane to fantastic" "It's just adynaton, but the campfire story was so impossibly scary none of us can sleep" Also, think "raining cats and dogs" or "when pigs fly"
Some would probably consider it a tad erudite. At least that's what I remember from earlier comments on words that are, let's say, less common. Or this one: The campfire story was so impossibly scary that it's easier for a camel to go through the eye of a needle.