The Story Starts Here! by Caroline Merola

From chapters.ca:
Little Wolf has decided that today, things are going to be done differently. It will be a contrarian day. Why? Because he said so! He will stand, not sit, for dinner – and he'll start with dessert. He's going to play the piano with his toes and wear his pants on his head. And when he says "The Story Starts Here," he means it – this book starts at the back and ends at the front. After Little Wolf's parents send him to his room to think about his backwards behavior, he decides to run away. But outside, everyone is running from a giant, shadowy monster. Readers will need to flip the book over to discover the monster's true identity.