One might wonder about the title of the prompt, how a nightmare can be funny.
A funny nightmare is an oxymoron. Two words with opposite meaning used side by side.
Nightmare is a really scary dream that is troubling while funny is the common habit of laughing or smiling at something.
Scary cannot produce laughter except for those that are psychotic, people that love evil and they enjoy seeing things spoil, and seeing people get hurt. This can be an exception. Because the major reaction to a nightmare is fright, people are usually scared after a nightmare. Some spend days nursing the dream.
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