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?