George and Harold's nemesis Melvin Sneedly goes from snooty to snotty in the sixth book in this #1 New York Times bestselling series by Dav Pilkey, the author and illustrator of Dog Man!George and Harold are up to their old tricks again, and when their latest prank makes a direct hit on school brainiac Melvin, he decides to get even! But in the blink of an eye — and the sneeze of a nose — the Bionic Booger Boy is born! Can Captain Underpants clean up this catastrophe, or will the mucous monster make a mess of things?