My Humongous Hamster Goes to School — Lorna Freytag

He's back, and bigger than ever! My humongous hamster heads to school in this sequel, and hilarity ensues. He eats all the packed lunches; he twirls in dance class; he plays hopscotch and takes a turn on the slide. But at the end of the day, he's tired, and so he shrinks back to normal hamster size . . . until the next time he's humongously hungry!