Mr Gum and the 13-Storey Underpants

Mr Gum and the 13-Storey Underpants is a 2021 book published by Scholastic. It is a crossover between the franchises Mr Gum, Storey Treehouse and Captain Underpants. Later on it crosses over into Jedi Academy 
== Trivia ==
* despite the fact that the Turbo Toilet 2000 has consistently been shown as working with Tippy Tinkletrousers, he does not in this book (rather working with Professor Stupido) because in the original books, they never met.
* It is a what if scenario where Stupido is sent to Uranus instead of The Moon in 39-Storey.
== Gallery ==
File:Prof Stupido.png|Stupido finds turbo toilet
File:Mr Gum.png|villains arguing
File:Uninvent.png|Uninvention of hypno-ring
File:Roan.png|Finding Roan
File:Wut.png|Effects of time travel
Category:Captain Underpants
Category:Storey Treehouse
Category:Mr Gum