Roverandom by JRR Tolkien

Roverandom is a novella written by JRR Tolkien for his child who lost his favorite toy. Roverandom, commonly called Rover, transforms into a toy after biting the wizard’s trousers. He will take many adventures to the moon and under the sea and meet a lot of fascinating and not-so-fascinating creatures. While this was written before The Hobbit, it was not published until much later.