Go with a pro. Once a man was walking on the road reading a newspaper. Get a copy here or subscribe. It is nothing but creativity and observation that you need in order to write your own hilarious masterpiece! Write a story of how Santa uses Rudolph's four legs and Rudolph uses Santa's heftiness to make things right and defeat the Grinch while reversing the effects of the spell and making everything back to normal.
Spice it up with these outside-the-box writing ideas and prompts… 1. How could that possibly be boring? The vibration that came from his singing made everyone whacky and they just couldn't stop laughing. Spend the time Googling or poring over social media posts?
Use odd juxtapositions. This is my first subject, and here are the laugh lines tied to that subject, and here is my second subject and the laugh lines tied to that subject, and so on. Copious notes. See which best suits your voice and your topic. This can be as simple as applying the funny word, phrase or sentence at the last possible moment.