Daisy Dreamer Posey, The Class Pest #7
From the back cover:
"Nerd alert! Guess what? I, Daisy Dreamer, have a big confession. I love school. You know what else I love? Posey. He's my totally true imaginary friend. So if I were to mix school and Posey together, then I would have the absolutely most perfect day. Obviously. Unfortunately, sometimes mixing two great things together makes for an absolutely huge mess, like grape juice and fluffy carpets, or lollipops and long hair. Well, I would not recommend mixing school and Posey together, unless you love having a classroom pest."