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Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers
Captain Underpants Robo-Boxers.jpg
Author Dav Pilkey
Illustrator Dav Pilkey
Country United States
Language English
Series Captain Underpants series
Genre Children's novel, comic science fiction
Publication date
January 15, 2013 (black and white)
September 1, 2020 (full color)
Media type Print (hardback)
Pages 221
ISBN 9780545175364
Preceded by Captain Underpants and the Terrifying Re-Turn of Tippy Tinkletrousers 
Followed by Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000 

Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers is the tenth book in the Captain Underpants series created by Dav Pilkey. It was published on January 15, 2013.


The giant zombie nerds move really slowly so the giant Zombie Nerd Harold actually crushed a giant ketchup packet. Tippy Tinkletrousers travels back to 10 minutes BEFORE Kipper and friends see him and freeze them. Tippy shrinks and abducts his past self to when George and Harold are about to be arrested. The boys travel back with their pets, but accidentally take Mr. Krupp with them. Big Tippy sends his smaller self back ten minutes to find where, then back there then, where the small ones zap themselves back and steal the Goosy-Grow 4000, which turns Tiny Tippy extremely massive. When Big Tippy attempts to use his nuclear bomb to kill Captain Underpants, Supa Mega Tippy zaps himself back in time (with his twin) and kicks Big Tippy and his bomb away into the Gulf of Mexico. When the bomb explodes, it blows a huge crater and kills the dinosaurs.

The five protagonists and their captor then travel to the African savannas where the boys and their pets gain the trust of some cavemen who inhabit the surrounding jungles. The cavemen are taught English through drawings and subsequently, the boys make the world's first comic book (which involves drawings of traps working on Tippy). The Neanderthals, inspired by the book, then set traps for Tippy and defeat him. He then sets off his freeze ray (which has been tampered with by his younger twin so that it could not be turned off), and the Goosy-Grow 4000 enlarges the ice which appears to make Crackers' condition deteriorate and causes the Ice Age (and freezing Tippy himself)

George and Harold are then transported to the future by Slightly Younger Tiny Tippy, who is now gigantic, thanks to the Goosy-Grow 4000. But it turns out they are now teachers at Jerome Horwitz Elementary, and Mr. Krupp is an old man. After getting rid of their evil future selves by vowing never to take life seriously, they snap their fingers, turning both Mr. Krupps into Captain Underpants, and they beat up Slightly Younger Tiny Tippy, who afterward attempts to use his nuclear bomb to blow up the entire galaxy. After that, Crackers and Sulu decide to save the entire galaxy by sending Slightly Younger Tiny Tippy and themselves back to the time before the universe existed (13.7 billion years ago). The three are then destroyed by Slightly Younger Tiny Tippy's giant nuclear bomb and the universe is formed. It also turns out that Crackers had laid a brood of eggs (revealing Crackers to have been a female.) and George, Harold, and the younger Captain Underpants all decide to take care of them. Suddenly, George's and Harold's nemesis, Melvin Sneedly, in a giant Robo-Squid called the "Super Squid", appears and captures George, Harold, Captain Underpants, and Crackers' eggs, taking them back to the future.


  • George Beard – A 9-and-three-quarters-year-old boy with a flat top.
  • Harold Hutchins – An 10-year-old boy with a bad hair-cut.
  • Mr. Krupp – George and Harold's mean principal who turns into Captain Underpants at the snap of a finger.
  • Captain Underpants – Mr. Krupp's alter-ego.
  • Sulu – The bionic hamster of George and Harold.
  • Crackers – The pterodactyl of George and Harold.
  • Tippy Tinkletrousers – The evil villain in the 4th book and 9th book, who is formerly known as Professor Poopypants.
  • Cave People – The people in the prehistoric area.
  • Ook and Gluk - George and Harold's cartoon caveboys.
  • Lily - Ook and Gluk's pet dinosaur.
  • Melvin Sneedly – George and Harold's nemesis.
  • Old Mr. Krupp / Old Captain Underpants – Mr. Krupp's 30-year older counterpart.
  • 39 3/4-year-old George and 40-year-old Harold - George and Harold's 30-year older counterparts. They are obnoxious teachers 30 years in the future.
  • Kipper Krupp - Mr. Krupp's nephew, who appeared in the previous book, where Tippy accidentally scared him and his friends, which resulted in a bad future. In this book, Tippy fixes his mistake by freezing the bullies so that another Tippy wouldn't scare them.
  • Bugg, Finkstein, and Loogie - Kipper's friends, who also appeared in the previous book.


  • Technically, neither the Talking Toilets nor the Turbo-Toilet 2000 should exist if Mr. Krupp was fired during George and Harold's kindergarten year. It was Mr. Krupp who prevented George and Harold from entering or even attending, the Invention Convention, which is what led them to mess up everyone but Melvin's inventions. He was also responsible for giving George and Harold detention for the rest of the year as a punishment, which is where they created the comic book that featured the Talking Toilets. Finally, he was the one who threatened to suspend them if he saw even one of them out of the detention room. This would lead to George and Harold copying their comic book on the PATSY 2000 out of desperation, and therefore creating the Talking Toilets.
  • In the intro comic, the Dandelion of Doom is featured as one of the villains Tippy inadvertently prevented Captain Underpants from defeating. However, George and Harold are shown as zombie nerds, which could only have happened if they didn't know about Zorx, Klax, and Jennifer's scheme. Since George and Harold created the Dandelion of Doom in an attempt to foil the aliens' plans to take over the world, neither of them could've created the Dandelion of Doom.
  • The first scene depicts Tippy Tinkletrousers changing history, however, he also caused several past events, similar to a predestination paradox, so it is unknown which one exists.
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