Who is doctor diaper in captain under pants?

Doctor Diaper is a character in the "Captain Underpants" series by Dav Pilkey. He is a villainous character, known for his evil schemes and obsession with diapers. His antics often create challenges for the main characters, George and Harold, as they navigate their adventures with Captain Underpants. Doctor Diaper's humorous and outrageous personality adds to the comedic tone of the series.