Benjamin Krupp/Synopsis

Villain Overview Synopsis Gallery

The history of the cruel and mean principal of Jerome Horwitz Elementary School Benjamin Krupp from the Captain Underpants franchise.

Early Life

Mr. Krupp in the fourth grade talent show.

Throughout the books and the film, not much of Mr. Krupp's early life is released. However, in The Epic Tales of Captain Underpants, the Netflix series, it's revealed that Mr. Krupp would have to learn farming by his abusive mother, Bernice, which he did not enjoy. During the fourth grade, Mr. Krupp would attend the talent show rather then milk the cows, like Bernice had wanted him to, and therefore, Bernice brought out fruits and vegetables to throw at him, causing Mr. Krupp to feel loss and reject and want the whole world to feel the same way.

During his teenage years, Krupp would be under the influence of a rivalry between him and Moxie Swaggerman, causing him to want nothing but to beat her from anything and everything that they did, though Krupp would fail at all times. As an adult, Mr. Krupp is still under the influence of this, yet Moxie denies ever knowing of his existence.

As the books reveal, at one point in his life, Krupp would get an unnamed brother, who gave birth to a child named Kipper.

Books

The Adventures of Captain Underpants

Mr. Krupp vowing he will get George and Harold.

Mr. Krupp is incredibly hot-tempered and an extraordinary principal. The narrator describes Mr. Krupp as the meanest and most sour old principal in the history of Jerome Horwitz Elementary School. He hated laughing and singing, in fact he hated all children together, as book 8 shows, he punishes children for minor offenses, like smiling and smelling funny, for his own satisfaction. He especially despised George and Harold. Mr. Krupp hates them, their pranks and especially the Captain Underpants comics. He vows to get them one day ("one day very, very soon" he claims).

The next day, after George and Harold ruined a big football game, they were reported to Mr. Krupp's office the next day. Mr. Krupp showed them their pranks on tape and wanted to find out who was responsible for the fiasco. George and Harold pleaded that they didn’t want to be killed for the rest of their lives, so Mr. Krupp (who put up with them for years) blackmailed the two boys to do his chores and not smile or he will threaten to give the tape to the football team, essentially using them for child labor. He even sadistically asked their teachers to give them extra homework.

After enduring Mr. Krupp's punishments, George ordered a 3D Hypno-Ring which is delivered 4–6 weeks later after he and Harold suffered the brutal and intense punishment by Mr. Krupp. He and Harold then used it on Krupp to get him to forget about their punishments, such as giving the tape of George and Harold to George and Harold themselves and replaced it with Harold's little sister's video tape of Boomer the Purple Dragon (a parody of Barney & Friends) sing-a long videos.

After getting back the tape, the two proceeded to get Mr. Krupp to do ridiculous acts, first making him think he's a chicken, then a monkey. After this, they tell him to think he's Captain Underpants. Mr. Krupp complies and begins smiling as he immediately strips down to his underwear. He rips the red curtain off his window and uses it as a cape, and begins stands triumphantly. The two found it funny, until he ran off and actually tried to fight crime.

Mr. Krupp as Captain Underpants.

His first stop is at the bank. When the two robbers see him, they are paralyzed with laughter and are immediately arrested. Captain Underpants also teases a policeman who tries to arrest him, but is saved by George and Harold. The three also witness two robots stealing a large crystal. Captain Underpants tries to stop them, but his cape gets caught on their van. He is dragged into an old abandoned warehouse where George and Harold hold onto his legs. There they meet Dr. Diaper, who has Captain Underpants tied up, but George and Harold escape. Dr. Diaper begins to power his machine to take over the world. George and Harold destroy the robots and free Captain Underpants. Dr. Diaper tries to stop them, but Captain Underpants throws his underwear over Dr. Diapers that make him defenseless.

All four escaped the Laser-Matic 2000 blast unharmed. Captain Underpants then tapes Dr. Diaper on a pole at the police station. When George and Harold arrive at the school, they have the captain put on Mr. Krupp's clothes and try to make him Mr. Krupp, but they've lost the manual and aren't sure how to do it. Desperate, George and Harold dunk water on Captain Underpants' head and managed to revert Mr. Krupp to normal before Mr. Krupp angrily tells the boys that he is going to give the tape to the football team. However, unknown to George and Harold, they have accidentally make Mr. Krupp’s hypnosis permanent. Now, Mr. Krupp turns back into Captain Underpants whenever he hears someone snap their fingers. Also, whenever "Captain Underpants" gets his head wet, he transforms back into his normal, grumpy self.

Captain Underpants and the Attack of the Talking Toilets

After encountering George and Harold learning about the new Invention Convention, Mr. Krupp reveals that after the previous year's "fiasco", George and Harold would be banned from presenting an invention this year. However, the boys do not approve of this and sneak in the gym that night to sabotage every students' inventions.

Melvin Richard Sneedly tattling on George and Harold.

The next day, the invention convention goes terribly as not a single invention (besides Melvin Richard Sneedly's PATSY 2000, as he had stuck a deal with George and Harold) works properly and instead "blows up" into the audience's face. After the convention ends, Mr. Krupp exclaims how he wanted to know answers as to why each invention exploded, which Melvin claimed he did.

After Melvin ratted out to Mr. Krupp that George and Harold were the reason that the convention failed, Mr. Krupp stormed into the study hall where he put George and Harold in and had Melvin reveal he tattle-taled. After sending Melvin away, Mr. Krupp made George and Harold write down the sentence, "I will never do anything which angers my handsome and charming Principal, Mr. Krupp, ever, ever again." However, after Mr. Krupp left, George and Harold made homemade "pens" made of multiple pieces of chalk screwed into tall wooden rods that covered up the whole chalkboard, and only had to write the sentence once for it to appear written twelve times. After three and a half minutes, every chalkboard was filled.

Since they still had a lot of time (116 and a half minutes to be precise), George and Harold wrote a comic book called "Captain Underpants and the Attack of the Talking Toilets", and wished to make multiple copies of it. However, since they would be suspended if Mr. Krupp or any other teacher saw them out of Mr. Krupp's office, they decided to sneak into the gym and use the PATSY 2000, which was a modified copier that copied images into real life, to try to make copies of their comic book. However, that resulted in creating the Talking Toilets, causing George and Harold to run out of the gym, in which Mr. Krupp caught them.

The Jerome Horwitz Elementary School Staff after learning about George and Harold's suspension.

Word quickly spread around the school that Mr. Krupp had successfully caught George and Harold and was able to suspend them, which gave the educators an idea to throw a party in the gym. However, George and Harold warned to not get into the gym due to the Talking Toilets, yet the teachers didn't listen. Almost immediately after opening the door, Mr. Kenny Brian Meaner, the gym teacher, was quickly eaten and flushed by a nearby Talking Toilet. Miss Edith Anthrope, the school secretary, ran away for her life, which left only Mr. Krupp, George, Harold, and Ms. Tara Ribble, a fourth grade teacher, paralyzed.

Ms. Tara Ribble snapping at a Talking Toilet.

After a brief silence, Ms. Ribble snapped at the nearby Talking Toilet and ordered it to go away, however, it wouldn't listen. However, Mr. Krupp had heard the snap and quickly ran into his office to change his outfit into that of Captain Underpants, as he had now entered his trance again.

Captain Underpants then runs around town collecting as many underwear as possible. After returning to school, she discovers that throwing her underwear down the toilet mouth doesn't do anything. After George and Harold realize they can use food from the cafeteria to stop the toilets, Captain Underpants uses the last pair of underwear to throw them into the mouth of The Talking Toilets. When the Turbo Toilet 2000 shows up, Captain Underpants tries to fight it. Unfortunately, the Turbo Toilet 2000 eats him before he can get a single hit and woke him out of his trance.

Mr. Krupp accepting defeat in Captain Underpants and the Attack of the Talking Toilets.

After the Turbo Toilet 2000 was defeated by the Robo-Plunger, Mr. Krupp quickly put clothes on and bellowed how he would lose his job if the superintendent found out about the mess the toilets made. However, George and Harold made a deal for Mr. Krupp to get rid of their detention, suspension, and let them be principals for the day if the Robo-Plunger cleaned the mess up. Mr. Krupp agreed, and soon the Robo-Plunger cleaned up the school and sent all of the toilets to the planet of Uranus.

The next day, George and Harold are shown to have used up the school budget to bring a carnival into the school's front yard, as Mr. Krupp, Ms. Ribble, Miss Anthrope, Mr. Meaner, and Melvin are seen writing sentences in detention.

Captain Underpants and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space (and the Subsequent Assault of the Equally Evil Lunchroom Zombie Nerds)

Mr. Krupp with the Cafeteria Ladies.

After the Cafeteria Ladies were pranked by George and Harold into believing that Mr. Krupp wanted cupcakes for his birthday and accidentally flooded the whole school with green goop, Mr. Krupp had a meeting with the ladies, who believed correctly that it was George and Harold that put out the recipe on their door. Mr. Krupp quickly jumped and said that it was obviously George and Harold, yet sadly the three cafeteria ladies didn't have proof. The only thing they had was a comic book George and Harold made that made fun of the ladies' liking. After Mr. Krupp refused to punish George and Harold without any proof, the cafeteria ladies had had enough and quit in front of Mr. Krupp.

After beckoning if there would be three new cafeteria ladies by the next day, three large women wearing a lot of makeup, which was really just evil aliens Zorx, Klax & Jennifer in disguise, came to apply for jobs as cafeteria ladies. After multiple denies of experience, credentials, or references, Mr. Krupp gladly hired them. As the new cafeteria ladies walked away laughing horrifically, Mr. Krupp went on scheming how to punish George and Harold, despite saying he wouldn't with the former cafeteria ladies.

Mr. Krupp yelling at the boys saying that they must eat lunch in his office the rest of the year.

After sending the trouble-making fourth graders into his office, Mr. Krupp punished them from ever eating cafeteria food again, which George slyly commented on how that was more of a reward rather than a punishment, though Mr. Krupp didn't find it funny. Mr. Krupp then stated that George and Harold were to eat in his office the rest of the year.

The next day during lunch, George and Harold brought disgusting lunches with them to gross out Mr. Krupp. Their plan succeeded, as Mr. Krupp went out of the office to "grab some fresh air". George and Harold then used the opportunity to change the letters on the lunch sign, yet found out that the whole school was turned into evil Zombie Nerds. After finding it out, George and Harold snuck in to find that the new cafeteria ladies were actually evil aliens that had created a plot to take over Earth. When George and Harold try to explain it to Mr. Krupp, he doesn't believe them and laughs at it, and even tries to prove that the students and faculty didn't turn into Zombie Nerds, as he sends in Miss Anthrope.

Mr. Krupp finding out Miss Edith Anthrope had been turned into an Evil Zombie Nerd.

Miss Anthrope walks in "dressed up as a nerd", yet Mr. Krupp states she always wore clothes like that. George and Harold then stated her skin was "pale and clammy" and that she "reeked of freakish zombified death", yet Mr. Krupp denies and says she always smelled and looked like that, which George and Harold reluctantly agreed that a school secretary and a Zombie Nerd can be easily mixed up as each other. However, Miss Anthrope soon leaned down and took a bite out of Mr. Krupp's desk, surprising him that she was a little more eviler than usual.

Zorx snapping his tentacle at Mr. Krupp, George, and Harold.

After finding out the truth, George and Harold sent Mr. Krupp to the evil alien cafeteria ladies, where Zorx grabbed onto Harold, causing him to scream, run away, and reveal the tentacles under the gloves Zorx was wearing. Angrily, Zorx shouted that George, Harold, and Mr. Krupp were fools and snapped his tentacle at them, causing Mr. Krupp to fall into his hypnotic trance again. Captain Underpants then runs away screaming before trying to buy a cheeseburger at a local shoe store, suggesting that he found George and Harold's match with Zorx, Klax, and Jennifer offensive (as implied by the warning in Incredibly Graphic Violence, Part 1).

When he returns, George and Harold are angry at him for leaving. However, their anger dissipates when the alien lunch ladies order the Zombie Nerds to hunt down George, Harold, and Captain Underpants. They run up to the roof and sneak into an alien spaceship where they find strange juice boxes (especially Extra-Strength Super Power Juice). After George and Harold sabotage the ship, Captain Underpants tells the boys his plan to move to safety with the toilet paper. When they ask if it will last, he reminds them that it is double-layered; therefore it must work. George and Harold grab his cloak to try to stop him, but as a result they are all taken out.

Toilet paper does not hold as expected. However, George and Harold's weight flattens the cloak, causing it to act like a parachute, allowing them to slowly fall down. As they approach the roof of the school, Captain Underpants is caught in the Deliriously Dangerous Death-Defying Dandelion of Doom while George and Harold land on the roof of the school. Hoping to save him, they reluctantly decide to give him superpowers. The next time the Dandelion of Doom gets around him, he uses his newly acquired superpowers to easily defeat the garden beast.

For the rest of the book, Captain Underpants stands by while George and Harold heal the Zombie Nerds with an a different special juice that brought them back to normal, Mr. Krupp was splashed with water and escaped from his trance, as the cafeteria ladies were presumably replaced, and George and Harold were presumably allowed to eat in the cafeteria again. However, something has changed in Mr. Krupp because he drank the superpower juice, so now whenever he becomes Captain Underpants, he can fly and use other superpowers, making it hard for George and Harold to keep their eyes on him (evident after the girl snaps her fingers in front of Mr. Krupp while she is listening to music). Instead of George and Harold watching from the window while witnessing Captain Underpants running into town. They are on his cloak and cling to him as he flies into town instead.

Captain Underpants and the Perilous Plot of Professor Poopypants

Mr. Krupp catching George and Harold in the act.

One day, Jerome Horwitz Elementary School had an annual field trip to Piqua Pizza Palace, yet at the school there was a long line to get to the bus, so as they waited, George and Harold decided to go change the letters on a sign nearby. However, once they finished they found Mr. Krupp hiding in a nearby bush to catch them in the act.

After a minor conversation with whether or not their joke was funny, Mr. Krupp had banned them from coming to the field trip, and even saying that because it was a cruel and unusual punishment, it was funny. Afterwards, Mr. Krupp sent George and Harold to the janitors' closet, and told them to use the supplies to clean the teachers' lounge as everyone else was in the field trip. Afterwards, the buses left with all of the teachers and students in, with all of the teachers laughing at George and Harold.

The Jerome Horwitz Elementary School Staff's comeuppance.

However, George and Harold had some tricks up their sleeves and "pranked" the whole teachers' lounge, which they say will be fun, but not for the teachers. An hour or so later, the buses arrived back at Jerome Horwitz Elementary School, and as the students got ready to leave, and Mr. Mortimer "Morty" Fyde, a fourth grade science teacher, was put on school bus duty, the rest of the teachers came to George and Harold and started teasing them, stating things like how "they wanted to bring George and Harold back a pizza, but they ate it on the way home", or how "the field trip was terrific!". However, after a while, the teachers got tired of teasing George and Harold and decided to relax in the teachers' lounge. However, it was dark, which caused Mr. Meaner to turn the lights on, which turned the ceiling fan on. Ms. Ribble then started to turn the faucet on, which caused the nozzle to spray cold water all on top of the teachers. After everyone was completely soaked, someone was finally able to turn off the faucet. At this moment, the ceiling fan was spinning at full speed, causing the powdered paste standing on top of the fan to spill on the wet teachers, making them sticky. Ms. Ribble, however, was not happy and went to check the fridge to make sure her diet coke was saved, where there the fan blew thousands of tiny Styrofoam pellets to land onto the sticky teachers, making it look like Styrofoam snowmen chasing the boys. While George and Harold might've gotten into a lot of trouble, Mr. Fyde was there watching the "snowmen" chase the boys.

Mr. Krupp letting Mr. Mortimer "Morty" Fyde go.

The next day, Mr. Fyde knocked on Mr. Krupp's door and announced his retirement due to how he believed that a few months ago he was eaten by a sentient toilet, then he started hearing cats and dogs in his room, imagined the school was flooded in green goop, and just the day prior he believed he saw abominable snowmen chasing two boys. While Mr. Krupp tries to explain how it could all be explained, Mr. Fyde continues on how he thought he saw a big, fat, bald guy in his underwear fly out the window. Due to Mr. Krupp's unawareness of his hypnotic trances, Mr. Krupp says that Mr. Fyde was crazy and let him resign, while wondering where he would find a fourth grade science teacher at a time like that. Luckily, a scientist from the fictional country of New Swissland, Professor Pippy Pee-Pee Poopypants, had been looking for a job to publicly show his new shrinking and enlarging inventions, yet couldn't due to his hilarious name. Poopypants was later hired off-screen.

Professor Pippy Pee-Pee Poopypants shrinking the school after losing his sanity.

For the next two weeks, Poopypants was barely able to keep his sanity from every child laughing at his name. However, he had hit rock-bottom after finding a comic George and Harold made making fun of his liking. Because of this, Poopypants enlarged a robot hamster suit to sit in, and shrunk the school.

After grabbing the school, Eyewitness Newswoman Ingrid Ashley came to Poopypants, who asked her if she had a pencil. After Poopypants enlarged the pencil to fit into the robot's hands, he found three empty billboards and started writing charts on each one of them. Each chart was filled with names that equaled to one letter, and when all revealed out, showed what a new name one might have.

After Mr. Krupp asked how the charts worked, Poopypants forced him to go through it. Starting with Mr. Krupp's first name, revealed to be Benny, which equaled to "Lumpy" on the first chart. Poopypants then knew Mr. Krupp's last name, Krupp, so he made Mr. Krupp look at the second and third charts. Since his last name started with "K", then his new last name would start with "Potty", and since his last name ended with "P", then his new last name would end in "Biscuits", revealing Mr. Krupp's new name to be "Lumpy Pottybiscuits". Poopypants then forced everyone to change their names or else they would be shrunken again, turning George and Harold into Fluffy and Cheeseball.

Because Fluffy and Cheeseball couldn't defeat Poopypants on their own, they came toward Mr. Pottybisuits and snapped their finger, sending Mr. Pottybisuits back into Captain Underpants. However, Chessball informs him that he has to be renamed Buttercup Chickenfanny. Captain Underpants is upset about his new name and refuses to accept it because he doesn't take orders from anyone. Just then, Fluffy orders him to bring them to Goosy-Grow 4000 and he (ironically) obeys.

On the way back, Captain Underpants gets shrunk yet again so that no one could see him. He ends up getting Goosy-Grow 4000 for Fluffy and Cheeseball and they tried to unshrink the school, but get thrown off by Professor Poopypants. Fluffy and Cheeseball use Goosy-Grow 4000 to make a large paper airplane to fly. The miniature Captain Underpants then places the paper airplane on the ground. As a steamroller comes by, Captain Underpants carries the boys away. Afterwards, Fluffy uses Goosey-Grow 4000 to make Captain Underpants big enough to fight Professor Poopypants. After Poopypants' robot was destroyed, Fluffy and Cheeseball enlarged themselves and the school back to normal while shrinking Captain Underpants. Poopypants was later arrested for his crimes, and after Harold played with a nearby garden hose, Captain Underpants was turned back into Mr. Krupp.

Captain Underpants and the Wrath of the Wicked Wedgie Woman

Mr. Krupp finding George and Harold, believing that they are onto something.

When George and Harold were sent to the Principal's Office by Ms. Ribble due to their comic making fun of her liking, Miss Anthrope had them print out the "Friday Memo", a schedule of all of next week's events, and pass it around to everyone. As Miss Anthrope left, George and Harold sneaked into her desk and changed the memo to make it look like a series of eventful things, such as a three-day weekend, a pajama day, etc. As they started to print them out, Mr. Krupp came into his office and asked what they were doing. George simply stated that Miss Anthrope told them to hand out the Friday Memo to all the classrooms, which Mr. Krupp simply told them to hurry it up. At that moment, Harold had a sneaky idea and got a piece of blank construction paper and told Mr. Krupp to sign it, as it was for Ms. Ribble's retirement. Mr. Krupp agreed to sign it and moved on with a suspicious look on his face at the boys.

After passing out all of the Friday Memos, George and Harold quickly came to Ms. Ribble's room just in time for her retirement party. However, they were caught changing the letters on a nearby sign and creating the rest of the card by Mr. Krupp, who explained how he had found out about the mocking comic book and sent the boys to detention. After Harold wished he could hand out the card to Ms. Ribble, Mr. Krupp took it out of Harold's hand and came to bring it to Ms. Ribble instead.

The Jerome Horwitz Elementary School Staff after learning about Mr. Krupp's "proposal"

Ms. Ribble's party was a disaster. The party started with the students being forced to sing an unpleasant retirement song to Ms. Ribble, which had taken so long all the chunky tofu ice cream Ms. Ribble brought had melted, yet everyone still had to eat it. Then, Ms. Ribble ripped up multiple retirement cards given to her by the students and even sent one kid to the corner of the room because his card was mistakenly pleasant. Then, Mr. Krupp gave Ms. Ribble the card Harold made. The cover read "Your One Hot Mama!", which made the kids gag. Afterwards, Ms. Ribble opened the card to read the message Harold wrote in, "Will You Marry Me?", and since it was signed by Mr. Krupp, everyone thought it was real, making the students gag harder. Mr. Krupp was speechless. He couldn't get a word in. The only thing that came out was "B-B-Bubba booba hob-hobba-hobba wah-wah". Mr. Meaner came and tried to congratulate Mr. Krupp, yet it sounded reluctant. However, Miss Anthrope came and gleefully gave out plans she had for a wedding between the two of them, though both Ms. Ribble and Mr. Krupp was confused.

The next week was very weird, even for Jerome Horwitz Elementary School standards. Weird things such as the students not showing up on Monday, the students showing up with their pajamas on on Tuesday, the girls having taped garlic and rotten egg sandwiches on their heads on Wednesday, multiple food fights in the cafeteria and the football team having tryouts in the teachers' lounge on Thursday, and everyone wearing bumblebee costumes and making funny faces for picture day. The whole week, Mr. Krupp was speechless except for those same words he stated the past Friday.

Ms. Tara Ribble denying her marriage to Mr. Krupp at the top of her lungs.

The next day on Saturday, the big wedding with Mr. Krupp and Ms. Ribble took place in the gym, where George and Harold made fun of the rabbi that came for the wedding. As the rabbi came to Mr. Krupp and Ms. Ribble, he asked the principal if he would have Ms. Ribble as his lawfully wedded wife. Like the past week, Mr. Krupp said "B-B-Bubba booba hob-hobba-hobba wah-wah". The rabbi then asked Ms. Ribble if she would take Mr. Krupp as her lawfully wedded husband, which caused her to shout "NO!" at the top of her lungs. Ms. Ribble then stated that she would not marry Mr. Krupp because of his terrible nose (despite the fact both of their noses are drawn the same way). Mr. Krupp then finally stated something other than "B-B-Bubba booba hob-hobba-hobba wah-wah", and stated that George and Harold had tricked the both of them, making the whole audience look at the two fourth graders. Chaos spread throughout the rest of the wedding, as Ms. Ribble tried to murder George and Harold, as Mr. Krupp seemingly left the gym early.

Mr. Krupp finding George and Harold's exceptional behavior suspicious.

That Tuesday, Ms. Ribble was called in absent, (as she had been hypnotized by George and Harold to change their failing grades, yet instead she turned into the supervillainess alter-ego from the mocking comic, Wedgie Woman), so Mr. Krupp was sent to be the substitute teacher for her. The day went by normally, however, George and Harold seemed, different. They weren't pranking the school, making inappropriate comics, etc. They were just being, exceptional students, causing Mr. Krupp to believe they were up to something. At recess, however, the children were playing kickball, and when Harold kicked the kickball up to "the corner of the page", Mr. Krupp took out the school rulebook and snapped at Harold because it was against the rules to kick school property into outer space. However, Mr. Krupp had fallen into his trance again after hearing his own snap.

After turning into Captain Underpants, it was revealed that George and Harold were actually robots created by Wedgie Woman to destroy Captain Underpants. The robots immediately chase after him. Captain Underpants mistakes the robots for George and Harold and remarks how happy he is that the boys have superpowers. They immediately use spray starch on him. He is hung by his underwear on a large pole and left trapped.

After George and Harold escape, he realizes that he still has his powers; they just believe they were taken away because of their comics. The boys try to tell him, but he won't change his mind. After failing to find any fabric softener, George and Harold make a comic and force Captain Underpants to read it. The comic explains that as a child, Captain Underpants swallowed a magical amulet that allowed him to instantly fight off the powers of starch. He then returns to his super state after trying to comment on the amulet metaphor. With his powers restored, he destroys Robo-George and the Harold 2000. As George and Harold dehynotized Wedgie Woman into a nice Ms. Ribble, they ordered Captain Underpants to splash water on his face. Quickly, Mr. Krupp was back to his old self.

Captain Underpants and the Big Bad Battle of the Bionic Booger Boy

Mr. Krupp with Miss Edith Anthrope.

One day, Mr. Krupp was in an aggravated mood and just needed some coffee to release his mind from his aggravation, so he yelled at Miss Anthrope if she had the coffee she presumably was supposed to make. Miss Anthrope shouted back at him that he should've gotten a cup himself, aggravating Mr. Krupp even further. Mr. Krupp then ordered Miss Anthrope to get a coffee, yet all she said was that she wanted a cup of coffee too, while he was at it. Mr. Krupp couldn't take it anymore, and simply took a newspaper and went to the faculty bathroom, where he met Ms. Ribble standing there, trying her hardest to not burst out laughing. Mr. Krupp ignored it and went into the bathroom, where two ketchup packets were squished from the toilet seat and splattered ketchup in Mr. Krupp's underwear. Mr. Krupp, who simply could not take it anymore, stormed into the cafeteria to punish George and Harold, ignoring Ms. Ribble's truthful claim that she did it and not them.

Melvin Richard Sneedly tattling on George and Harold once again.

As he stormed into the cafeteria, he noticed every student from every grade except the fourth grade had fallen victim to the prank. Before long, Mr. Krupp had found George and Harold and proceeded to put them into detention, with the help of Melvin stating that George and Harold were the inventors of the prank, even if they weren't the administers to it. George and Harold proceeded to take revenge and created a comic book making fun of the liking of Melvin, causing Melvin to want revenge on his own and use his new invention, the Combine-o-Tron 2000, to combine himself and a super-powered robot together. The experiment sadly failed when Melvin's allergies got the best of him, and he sneezed just before the combining began, creating the Bionic Booger Boy.

One day, Ms. Ribble had called in sick with a cold, forcing a reluctant Mr. Krupp to substitute. After finding out about Melvin and his colossal sneezes, Mr. Krupp proceeded to inform the children that he and Miss Anthrope would send them on a field trip to Snoddy Bros. Tissue Factory to learn about how blow-rags are produced, causing Melvin to freak out. On the field trip, the children's tour guide, Mr. Snoddy, collected and gave out numerous tissues to every child, including Melvin, who had freaked out so much that his robot body made him grow thirteen feet tall. Sadly, Mr. Snoddy was very dimwitted, and enjoyed throwing out multiple more tissues, causing Melvin to grow so high, it collapsed the factory.

Miss Edith Anthrope being kidnapped by Melvin Richard Sneedly/The Bionic Booger Boy.

In an attempt to stop Melvin, Mr. Krupp and Miss Anthrope came out of the collapsed factory and tried to reason with him. However, it did not reach the bothering child and instead aggravated him, causing him to kidnap Miss Anthrope. In a moment of cowardness, Mr. Krupp ran away, stating he would find and acquire help, yet instead hid behind a curtain in the design of Captain Underpants' cape. Annoyed, George and Harold, who were also hiding behind that very curtain, snapped their finger to bring Mr. Krupp back into his unfortunate trance.

As Captain Underpants, he was able to rescue Miss Anthrope, yet unfortunately had lost his cape in the process. The superhero was turned into his aggrivating, grouchy alter-ego after Miss Anthrope congratulated and gave thanks to him by kissing him. Soon enough, the Bionic Booger Boy was in capacity of our heroes, freightening Miss Anthrope and causing her to run away. However, Mr. Krupp did not dare to do so and instead simply yelled at George and Harold, before The Bionic Booger Boy had kidnapped and swallowed Mr. Krupp whole.

Carl, Trixie and Frankenbooger morphing into sentient beings.

After Sulu the Bionic Hamster, Melvin's former pet hamster-turned-George and Harold's current pet hamster, had defeated the mucus filled monster, Melvin's mother and father, Gaylord and Cindy Sneedly, went up to their giant son and used the Combine-o-Tron 2000, which was reprogrammed by simply switching the batteries around, to separate everything from their son. However, Mr. Krupp and Melvin had been morphed together, forcing Gaylord to zap them with the Combine-o-Tron 2000 once more. However, was still assumed off about Mr. Krupp and Melvin, yet before one could find out why this certain phenomenon was happening, three mucus-filled chunks of robots started to morph into a sentient being, and soon enough, the Robo-Boogers Carl, Trixie and Frankenbooger were created, who destroyed the Combine-o-Tron 2000 and chased our terrified protagonists throughout the city of Piqua, Ohio, as well as ending off the first of two halves of this story.

Carl, Trixie and Frankenbooger cornering and jumping at our protagonists.

Our protagonists were chased by the Robo-Boogers until they were cornered in a "dead-end" alley, where they cowered in fear and shut their eyelids, knowing that their end was near. However, Sulu the Bionic Hamster was not alarmed, and instead of cowering in fear, Sulu had extended his robotic jaw and swallowed up the alarming Robo-Boogers, before spitting the Robo-Boogers out to beyond our planet of outer space.

"Mr. Krupp" getting smacked in the head by Cindy Sneedly.

While George and Harold simply assumed that "their adventure was over", their adventure had sadly only just begun. As the gang had walked off to the Jerome Horwitz Elementary School, they had a very interesting conversation that caused much confusion to them all, as Mr. Krupp had stated he wanted his hamster back, despite how it was originally Melvin's and not his, and Melvin stated that the three of them would all be sent into detention. At that moment, Gaylord and Cindy Sneedly had found Melvin and tried to reveal how happy they were when they found out he was okay, yet for an unknown reason, Mr. Krupp came up to them wanting to hug them, yet instead was smacked on the head by Cindy's purse. While Mr. Krupp was getting smacked in the head with a purse, Melvin went into the school, where he found Miss Anthrope and yelled at her that he would fire her if she didn't give him his coffee. However, this did nothing but aggravate Miss Anthrope, who was having a particularly terrible day. So, Miss Anthrope gave Melvin a wedgie and hung him on a nearby coat hook and stormed out of the school.

Melvin and Mr. Krupp discovering they switch bodies.

As George and Harold, who was inside the school watching the entire sequence of events, tried to take Melvin off the coat hook, Mr. Krupp came and asked the nearby people if they could help him. After Mr. Krupp put some clothes on, George and Harold, who had already figured out what had happened, tried to explain to them that in the process of separating the two of them, their minds were swapped, and so then at that current time, Mr. Krupp's brain was inside of Melvin's childish body, and vise versa. After showing them a mirror, Melvin in Mr. Krupp's body, who was titled "Mr. Melvin" by the narrator to avoid confusion, stated that he would be working on creating another Combine-o-Tron 2000, yet it would take around six months. Mr. Krupp in Melvin's body, who was also titled "Kruppy the Kid" by the narrator, yelled at how it would be improbable to have the body of Melvin for the next six months. After Mr. Melvin exclaimed how the Combine-o-Tron was hard to make unlike building a robot, a time machine, or another PATSY 2000, George stated that all Mr. Melvin had to do was create a time machine, go back in time to before the Robo-Boogers destroyed the Combine-o-Tron 2000, and come back with it. Mr. Melvin denied the idea, however, he pretended to come up with it on his own and snapped his fingers at the same time, bring Kruppy the Kid into a trance again and flies away despite George and Harold trying to stop it. Mr. Melvin then gets George and Harold to tell him all about Captain Underpants.

Meanwhile, Captain Kruppy the Underpants Kid spends the next two days trying to help the citizens of Piqua, but his attempts often fail. At first he tries to help the old ladies across the street, but then he finds a kitten stuck in a tree. Captain Kruppy rescues the kitten but leaves the old ladies in the tree. Next, while flying over the football field, Captain Kruppy notices a football and mistakes it for a UFO. He then grabs it and flies down to the football field to announce his intention to destroy the football, inadvertently causing the Purple Dragon Sing A-Long Friends to lose their biggest game of the year. Finally, Captain Kruppy breaks some skateboarders' skateboards and spanks the skateboarders for skateboarding in a no-skateboarding zone.

Upon retrieving the Combine-O-Tron 2000 the day before yesterday, Mr. Melvin gets George and Harold to call Captain Kruppy so they can switch bodies. They do, and Captain Underpants flies out the window... only to fall three stories to the ground. He thinks he has forgotten how to fly, but then discovers that his powers have been transferred into Melvin Sneedly's body.

Earlier in the book, Carl, Trixie, and Frankenbooger grab a spaceship that was exploring Uranus, where the robot and toilets from book 2 are. They are hanging on the spaceship as the spaceship returns to Earth. Once on Earth, they begin destroying the center of the spaceship. Captain Underpants, despite having no superpowers, decides to go after the Robo-Boogers with George and Harold following him.

They initially lose to the Robo-Boogers, but find that the Robo-Boogers die when they come into contact with the oranges (the vitamin C in the oranges counteracts the cold and flu viruses that made the boogers evil). They defeat Carl this way, but Trixie and Frankenbooger are more careful and avoid the oranges. Captain Underpants defeats the Robo-Boogers by standing on top of John's House of Toilets (the top of the store is a giant toilet lid) and doing an annoying dance. The Robo-Boogers begin climbing the building where they are hit by a well-placed Squishy. Soon, George and Harold have to answer questions from Ingrid Ashley and her crew, but Melvin arrives and lies to the Eyewitness News group, claiming that he defeated the Robo-Boogers with his superpowers.

While Big Melvin tries to get Captain Underpants to bow to him, George and Harold sneak back into the school. George and Harold then return with Combine-o-Tron 2000 and Forgetchamacallit-2000. They then use the Combine-O-Tron 2000 on Big Melvin and Captain Underpants, giving Captain Underpants his superpowers again. With Forgetchamacallit 2000, they also erase the memories of the news crew and TV audience. As George and Harold leave to go back to their treehouse, they use a water fountain to splash Mr. Krupp with water and turning him back to his old self.

Captain Underpants and the Preposterous Plight of the Purple Potty People

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Captain Underpants and the Terrifying Re-Turn of Tippy Tinkletrousers

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Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers

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Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000

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Captain Underpants and the Sensational Saga of Sir Stinks-A-Lot

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Dog Man: For Whom the Ball Rolls

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Movie

Mr. Krupp pointing his finger.

In the film, Mr. Krupp is bent on busting George and Harold of their multiple pranks they had done to him and the other staff, though he finds it upsetting that he hasn't gotten any evidence to have them punished. He also hates their Captain Underpants comics as he forbids them from creating any in the school grounds, even tearing up their latest one detailing the origins of the superhero, much to their horror.

Mr. Krupp as Captain Underpants.

George and Harold's pranks come to an apparent end after they tamper with a toilet invention called the Turbo Toilet 2000 made by the school's snitch Melvin Sneedly. With that in mind, Mr. Krupp happily decides to place George and Harold in separate classes in order to stop their friendship and their pranks. But before Mr. Krupp could fill out the paperwork to make it happen, George hypnotizes Mr. Krupp with a 3D Hypno-Ring he got out of a cereal box; the boys see that Mr. Krupp bears a resemblance to Captain Underpants without his toupee and command him to be Captain Underpants. However, this quickly backfires when Captain Underpants begins causing some problems around Piqua, thinking he’s a real superhero with superpowers.

The boys discover that they can turn Captain Underpants back into Mr. Krupp by splashing water on him and can turn him back by snapping their fingers. Believing that Mr. Krupp will continue with his plan to separate them, they decide to settle with Captain Underpants but insist that he be dressed up as Mr. Krupp under the pretense of a secret identity, to which Captain Underpants agrees. His sudden personality change even manages to attract the attention and affection of the school's shy lunch lady Edith.

Mr. Krupp’s fury.

The boys even learn (after exploring his house) that Mr. Krupp might not be as evil as they thought, but has rather been lonely for most of his life. Eventually, Mr. Krupp turns back into himself after a rainstorm occurred, learning that George and Harold have started a fair at the school without his knowledge. Having enough of their antics, Mr. Krupp angrily sentences the two boys to separate classes, much to their dismay. Despite being satisfied that he finally punished the boys as promised, Mr. Krupp finds himself moping in boredom after looking at the casserole that Edith made for him, feeling so depressed that he never even got a chance to ask her out on a date.

During the fight against Professor Poopypants and the Turbo Toilet 2000, the boys change Mr. Krupp into Captain Underpants to help them fight off the villains. Unfortunately, Poopypants gets the Turbo Toilet 2000 to swallow Captain Underpants whole before taking George and Harold as hostages. However the boys' sense of comedy managed to help crash the Turbo Toilet's system, allowing Captain Underpants to escape after consuming the rotten leftovers inside.

Captain Underpants with superpowers.

The leftovers also allowed Captain Underpants to obtain superpowers to finally defeat Poopypants, becoming a true hero to the public. However, George and Harold destroy the 3D Hypno-Ring in an attempt to permanently change him back into Mr. Krupp, as they know that they can't control Captain Underpants. Feeling sorry for Mr. Krupp because he has no friends, the boys set him and the lovestruck Edith up on a date. This made Mr. Krupp have a change of heart, even returning the comics he took away from George and Harold while admitting that they are funny.

However, the toxic waste from the Turbo Toilet 2000 transforms all the toilets into an army of Talking Toilets which attack the restaurant at which Mr. Krupp and Edith are dining. Upon snapping his fingers while calling for a check after seeing a toilet eating up a citizen in horror, Mr. Krupp once again becomes Captain Underpants, carrying George and Harold away to help him fight the Talking Toilets, which confuses George, as he thought destroying the ring would destroy the hypnotism.

Netflix Series

Mr. Krupp in the TV Series.

Mr. Krupp, alongside his superhero alter ago, Captain Underpants, where he serves the deuteragonist of the series once again, where he is now portrayed as incredibly stupid and mean. He has also developed a love for guacamole and salami, though he developed salami intolerance due to eating it too fast. Mr. Krupp's shown to be not very bright, even as a principal, and has always been a bully.

He often joins forces with Melvin to either get revenge on George and Harold or to fulfill his own evil plans. He is shown to take sadistic joy in torturing kids such as using air raid sirens at recess, frozen toilet seats and shock lockers. However, there are still times where he is somewhat decent, though it's usually because it would benefit him, such as when he allowed the students and faculty of Jerome Horwitz Elementary School to go to space so he could have a chance to finally outshine his Moxie Swaggerman, by attampting to serve as the Schoolship's leader but fails horribly, even sending the School Spaceship to a planet called Utopiqua and their crash landing which would got everyone almost killed. On a few occasions, he was forced to team up with George and Harold, such as he joined the M.I.S.F.A.R.T.S to rescue Melvin form the Bigylans in "The Confusing Crisis of the Conniving Captive".

After Melvinborg takes over the school in Season 2, Mr. Krupp ends up becoming the new vice principal and is subjected to a series of difficult and humiliating chores to keep his job. This ranges from trivial things like mowing the lawn despite his allergies to messed up territory like performing on stage while dressed as a rabbit in front of his former peers to be laughed at.

In "The Costly Conundrum of the Calamitous Claylossus", Mr. Krupp enlists Melvin Sneedly's assistance in terrorizing the kids by making rumorous student Bo Hweemuth his shark in exchange for keeping them straight with the promise of getting Melvin into his dream school.

He’ll hire anybody to be a teacher, even a baby, as shown in "The Jarring Jerkiness of Judge J.O.R.T.S.". He even wanted absolute power as in "The Crazy Caustic Spray of the Contagious Cruelius Sneezer", when he pretended to become an emperor on a field trip to Rome. He even abandon George, Harold and their friends and Mr. Meaner in the woods in “ The Bad Beat of the Blah Borelock” to get rid of them.

Mr. Krupp grining evilly.

In the interactive special, he even try to destroy George and Harold’s treehouse once all for all, which would be bad for the environment and is also a waste of money and shelter. In the Halloween special, he tried to help Melvin to cancel Halloween and later made it illegal, so he have peace and quiet. In the same special, he stole a bunch of avocados to make a relaxing guacamole bath and later wanted to turn George and Harold in for Hack-O-Ween. In the Christmas special, he has George and Harold to directed the Christmas play so he won’t have to, which the boys to switch the play's focus to Blissmas. After the show is over, the parents are upset and lash out at Mr. Krupp. Mr. Krupp then forces George and Harold to perform manual labor by cleaning up the toilets for punishment.

Whenever he transforms back from Captain Underpants, he doesn't seem to know why he’s in his underwear after being soaked in water.

A brainwashed supervillain alter-ago of Captain Underpants called "Captain NanoPants" was created after being taken over by the Nanobots who only appears in "The Taxing Trauma of the Treacherous Tattle Trials". A dream version of Captain Underpants called "Captain Ultrapants" was also created, who only appears in "The Monstrous Mayhem of the Massive Melviathan".