Who Invented Underpants? Otros libros de esta serie

The Power of Pooping The Power of Pooping
The Power of Pooping
2022
Why Do Roller Coasters Make You Puke? Why Do Roller Coasters Make You Puke?
Why Do Roller Coasters Make You Puke?
2017
Can Holding in a Fart Kill You? Can Holding in a Fart Kill You?
Can Holding in a Fart Kill You?
2015
Why Does Bright Light Make You Sneeze? Why Does Bright Light Make You Sneeze?
Why Does Bright Light Make You Sneeze?
2018