History Trivia / CaptainUnderpants

* GeniusBonus:
** The series takes place in Piqua, Ohio. In real life, Piqua is the location of the (now retired) Great Outdoor Underwear Festival.
** In book four, the buses for the field trip say Miami County. The real Piqua actually is located in Miami County.
** In book 10, Tippy's gigantic bomb becomes the explosion that wiped out the dinosaurs, and it's mentioned that it was kicked to the Yucatan Peninsula. This is the real life location of where the asteroid that killed the dinosaurs landed.

* AuthorAppeal: Dav's a bit of a music fan, making references to Music/TheBeatles and the like with frequent puns to songs.
** He also seems particularly fond of making references to the Paper Lace song ''“Billy, Don’t Be A Hero”'', seeing as how he’s done variations of that joke in FOUR different book series (''Captain Underpants'', ''Super Diaper Baby'', ''Ook & Gluk'', and ''Dog Man'')!

** Some copies of one of the books come with a real life version of the Hypno Ring. It's just a plastic toy though, no mind control...or is it?

** At the end of ''Captain Underpants and the Preposterous Plight of the Purple Potty People'', two additional books were teased, neither of which having been heard from since:

* WriteWhatYouKnow: Everything that happened to George and Harold happened to Dav Pilkey in grade school. He constantly got in trouble with his teachers for drawing comic books, which themselves were based on things that were happening to him at school then and there. Captain Underpants himself was inspired by his second grade classmates laughing at the word "underwear," to which his teacher furiously replied "UNDERWEAR IS NOT FUNNY!!" In Pilkey's words, he learned from the experience that "underwear is powerful."

*** ''[=FrankenFart=] vs. the Bionic Barf Bunnies from Diarrhea Land'', a book supposedly written by Evil Dav Pilkey from the MirrorUniverse depicted in Book 8.

* WriteWhoYouKnow
** Melvin was based on an [[InsufferableGenius annoying classmate]] [[https://wolfnanaki.tumblr.com/post/143361417037 Dav knew in sixth grade]] (who he referred to as “Michael Sneedman”, to protect the kid’s identity).

** Melvin was based on an [[InsufferableGenius annoying classmate]] Dav knew in sixth grade (who he referred to as “Michael Sneedman”, to protect the kid’s identity).

** The end of ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' teased a sequel called ''The Adventures of Ook and Gluk Jr.: Kung-Fu Cavekids in Outer Space'', which was supposed to be "Coming Soon-ish!!!" This may, however, have been a LampshadeHanging of the above two instances. Given that the original book was pulled from publication in 2021, it's safe to assume that no sequels will ever be written.

* OldShame: In the wake of an increase in hate crimes against Asian-Americans and Pacific Islanders in 2021, Pilkey expressed regret towards ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' for having “harmful racial stereotypes and passively racist imagery” against Asians and had the book pulled from print. [[Administrivia/RuleOfCautiousEditingJudgment It is debatable whether or not there really were any passive racial stereotypes to speak of.]]

* OldShame: In the wake of an increase in hate crimes against Asian-Americans and Pacific Islanders in 2021, Pilkey expressed regret towards ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' for having “harmful racial stereotypes and passively racist imagery” against Asians and had the book pulled from print.

* WriteWhatYouKnow: Everything that happened to George and Harold happened to Dav Pilkey in grade school. He constantly got in trouble with his teachers for drawing comic books, which themselves were based on things that were happening to him at school then and there. Captain Underpants himself was inspired by his second grade classmates laughing at the word "underwear," to which his teacher furiously replied "UNDERWEAR IS NOT FUNNY!!" In Pilky's words, he learned from the experience that "underwear is powerful."

** The end of ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' teased a sequel called ''The Adventures of Ook and Gluk Jr.: Kung-Fu Cavekids in Outer Space'', which was supposed to be "Coming Soon-ish!!!" This may, however, have been a LampshadeHanging of the above two instances.

* OldShame: In the wake of an increase in hate crimes against Asian-Americans and Pacific Islanders in 2021, Pilkey expressed regret towardss ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' for having “harmful racial stereotypes and passively racist imagery” against Asians and had the book pulled from print.

* UnintentionalPeriodPiece: George and Harold initially hypnotize Krupp because they were fed up with him blackmailing them with a VHS tape that has dirt on them.

** Mr. Krupp was a combination of his second grade teacher, who would ''tear his drawings up in front of him'', and his high school principal, who told him that he had no future as a cartoonist. Jerome Horvitz in general is [[SuckySchool intended to represent what a miserable and soul-crushing experience his school was]].

** Mr. Krupp was a combination of his second grade teacher, who would ''tear his drawings up in front of him'', and his high school principal, who told him that he had no future as a cartoonist.

** The end of ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' teased a sequel called ''The Adventures of Ook and Gluk Jr.: Kung-Fu Cavekids in Outer Space'', which was supposed to be "Coming Soon-ish!!!" Possibly a parody.

* WhatCouldHaveBeen: ''The Terrifying Return of Tippy Tinkletrousers'' was originally going to have a plot involving Tippy escaping prison and having revenge on George, Harold and Captain Underpants. However, due to its DevelopmentHell status the plot dramatically changed to a time travel-themed two-parter.

** The end of ''The Adventures of Ook and Gluk: Kung-Fu Cavemen From the Future'' teased a sequel called ''The Adventures of Ook and Gluk Jr.: Kung-Fu Cavekids in Outer Space'', which was supposed to be "Coming Soon-ish!!!"

* {{Defictionalization}}: Some copies of one of the books come with a real life version of the Hypno Ring. It's just a plastic toy though, no mind control...or is it?

** As noted above, book 9; ''The Terrifying Return of Tippy Tinkletrousers'' didn't come out until 2012, '''''six years''''' after book 8.

** As noted above, book nine, ''The Terrifying Return of Tippy Tinkletrousers'' didn't come out until '''''six years''''' after book eight.

* WordOfGod:
** George and Harold, like [[AuthorAvatar Dav Pilkey himself]], suffer from both ADHD and dyslexia.
** George's future wife in Book 12 is named Lisa.
** Mr. Meaner's full name is Kenny B. Meaner.
** Harold’s birthday is March 6th, and George’s is July 11th.
** George’s middle name is “Robert”, and Harold’s is “Michael”.
** Melvin’s birthday is December 25th.
** Mr. Krupp’s birthday is April 1st.
** Before they married Future George and Future Harold respectively, Lisa and Billy’s full names were “Lisa Bobeesa” and “[[PunnyName Billy Doanbee-Ahiro]]”.
** Melvin’s Mother’s name is Cindy, and like her husband Gaylord, she is also a professor.
** Melvin’s middle name is “Richard”.
** While Mr. and Mrs. Sneedly are [[{{Workaholic}} constantly busy with their work]] (to the point of coming across as somewhat [[ParentalNeglect neglectful of their son]]), [[HeartwarmingMoments they actually do try their best to be good parents when it comes to Melvin]].
** The reason why Melvin’s family has a cat (Danderella), despite the fact that he’s allergic to her, is because his parents got her before he was born, but they just didn’t have the heart to get rid of her after it became clear that Melvin was allergic.
** In Book 12, Meena and Nik (Future George and Lisa’s children) are 6 and 4 years old respectively, and Owen and Kei (Future Harold and Billy’s adopted twins) are only 3.
** Mr. Krupp has a younger brother named Jasper, who is the father of Kipper.
** [[CanonForeigner Edith the Lunch Lady’s]] birthday is February 14th.
** Harold’s Mom’s name is Grace, and George’s Mom and Dad’s names are Barbara and Moses (but his friends call him “Moby”).
** Harold’s little sister Heidi is 6 years old.
** Harold met Billy when they were in college. They were in the same improv comedy group together.