Picture books where the main character goes through a process of trying on different personalities, in most cases returning to their original self. Also try subject term "individuality - juvenile fiction" for similar stories.
Spoon by Amy Krouse Rosenthal; Scott Magoon (Illustrator)
Call Number: PZ8.ROSE
Edward the Emu by Sheena Knowles; Rod Clement (Illustrator)
Call Number: PZ8.KNOW
I Don't Want to Be a Frog by Dev Petty; Mike Boldt (Illustrator)