WRITING OBSTACLE
Write a story that includes a refrain that changes its meaning in the course of its narrative.
An easy way to do this may be to use a phrase that contains homographs - words that are spelt the same but have different meanings - allowing you to change the meaning of the phrase.
Opposite Day
(Not really the prompt but I think it will be funny)
In opposite land everything is topsy turvy. What’s down is up and up is down so be prepared to see fish in the sky and birds in the sea. They start with dessert first and end the meal with vegetables. The people grow down and not up.