".....the storybook or the costume?"
At our elementary school, we have a Storybook Parade, each year. It's always held right around Halloween. The idea is for the students to come, in costume, based on a character in a storybook. They don their costumes, carry their books, and parade around the school park, for an adoring parental audience.
The challenge, at our house, seems to be that my children decide what costume they want to wear, first. Then, they (and, in turn, I) frantically search for a book that connects, somehow.
I am certain that this was not the school's intent. This is definitely backwards.
I have observed, in previous years, many Harry Potters, Cat in the Hats, An Old Woman in a Shoe, and even Fern, from Charlotte's Web. Not us.
The best example, yet, of our family's reverse decision-making is my daughter's choice this year. She is INSISTENT that she wear her TCU Cheerleader Outfit. While I am thrilled to be getting some extra use out of this ensemble, it is definitely not inspired by a storybook.
Unless we suddenly discover a cheerleader character in a book we already own, she will march in the parade, carrying the TCU Football Program. That's reading, right?