"Doug is Quailman" is the first part of the twelfth episode of season one of Nickelodeon's Doug.
- Doug Funnie/Quailman
- Roger Klotz/Dr. Klotzenstein
- Patti Mayonnaise
- Skeeter Valentine
- Beebe Bluff
- Chalky Studebaker
- Professor Ogie
- Lamar Bone
Doug imagines that he is Quailman while drawing a comic book of the same name and must use his powers to battle the evil Dr. Klotzenstein (Roger), who is using his "brain beam" to suck the smarts from all the kids at school.
The episode starts with the introduction of one of Doug's alter ego Quailman and his sidekick Quaildog. Doug is later seen writing his comic in his room and signs his name on it, as well as Porkchop putting his pawprint on it. Doug and Porkchop shake hands and Porkchops leaves ink on Doug's palm.
The episode starts with Quailman and Quaildog at their headquarters named "The Thicket of Solitude" watching the news of Dr. Klotzenstein draining the brains of the students using his "brain beam." The villain is also known as Klotzilla, Baron von Klotz, and Cyklotz. The villain is also said to be disguised as a casual Roger himself. Quailman then states that he and Quaildog must be on the alert.
The next day, during science class, Roger frightens Patti with a frog, saying that it is his Aunt Fibeon as a science joke. The science teacher named Professor Ogie then tells the class that they are having a pop quiz, much to their stress. But Roger is surprisingly prepared for the quiz. When the teacher asks Patti how many bones are in a human body, Patti confidently begins to answer, only for Roger to drain her brain with his brain beam, leaving her stumped. Roger answers the question, saying that there are approximately 200 bones in the body. When Beebe gets asked what planet has the longest rotation around the sun, Roger uses his brain beam to drain her brain as well, answering that Pluto is the answer. Skeeter then gets asked what Newton's third law in motion, but predictably gets his brain drained by Roger's brain beam, and Roger states that there is an equal but opposite reaction. As Professor Ogie leaves to get Mr. Bone to witness Roger's sudden "intelligence", Roger drains everyone's brain and makes himself smarter than all of them combined. He even plans to drain the brains of everyone from around the world. Patti makes the "quail call" for help and Quailman arrives at the school to find the students droned out of their mind. When Roger realizes Quailman's presence, he transforms into Dr. Klotzenstein. As Quailman breaks through the window, he asks the students what scheme the villain is up to. But Dr. Klotzenstein tells the superhero that he won't get information from the other students due to their brains being stolen from them by his brain beam. Quailman demands Dr. Klotzenstein to surrender, but when the latter refuses, Quailman calls in Quaildog to assist him and tells the villain to give up. Dr. Klotzenstein suggests that they should collaborate instead and rule the world, right before attempting to use his brain beam on the superhero, who suppresses it by using his Quail eye. But after a while, the brain beam proves to be too potent and soon, Quailman tries other powers. He hides behind the desk and gets an idea when he sees a frog. Quailman pretends to surrender and as Dr. Klotzenstein uses his brain beam to fire at Quailman, the superhero uses the frog as shield from the villain's brain beam. The villain then gains the intelligence of the frog and starts eating flies, and Quailman uses the quail whistle to restore everyone's intelligence. When Professor Ogie and Mr. Bone walk into the classroom, Quailman takes the villain with him as he flies away, with Quaildog trailing behind with Stinky in his paws.
At the gymnasium, Mr. Bone offers Quailman and Quaildog permanent hall passes for their work and the superheroes fly away, ending the story.
Back in Doug's room, he leaves with Porkchop to get a Peanutty Butty. As they leave, the drawing of Quailman and Quaildog is shown on Doug's drawn-out comic and come to life, showing Quaildog blowing bubble gum and the gum explode all over him.