When your main villain has the name Professor Poopypants, it's pretty hard to shy away from toilet humour.

And though it has been knocked as the lowest form of humour — something referenced several times in Captain Underpants: The First Epic Movie —  the new film, out Friday and based on the popular Dav Pilkey book series, embraces it. 

"We'd be betraying the source material if we didn't go there a little bit," jokes the film's director, David Soren, who was born in Toronto and studied animation at Sheridan College in Oakville, Ont. His aim was making a smarter sort of toilet humour, brushing aside the "upper crusty approach to comedy" that pooh-poohs it.

"We did keep the bar very high for ourselves in terms of when we went there and making sure if we were going to do a joke like that, then it had to be really funny."

There are fart, poo and pee jokes, courtesy of the animated film's main characters and fellow fourth graders George (Kevin Hart) and Harold (Thomas Middleditch). The quirky duo make comics, pull pranks and end up hypnotizing their principal into thinking he is one of their comic book creations, Captain Underpants (Ed Helms).

While this is Underpants' first foray into film, the series of books turns 20 this fall. It has sold millions of copies and spawned spinoffs like Super Diaper Baby and Dog-Man.

Making toilet humour smart with Captain Underpants1:46

'The boys are actually good kids'

Not everyone found the series' toilet humour funny, with some parents and schools banning the books. It has frequently topped the American Library Association's annual list of most frequently challenged books for complaints about "offensive language", and for being "sexually explicit" and "unsuited to age group."

Pilkey has spent years brushing off the criticism and did so again on CBC Radio's q last month: "I write books for children, and so there's lots of kids' stuff in the books. And [for] many adults, it just doesn't match their tastes. So if an adult says, 'That's not for me', I would say, 'Well of course. It's a children's book. Of course it's not for you.'"

Soren also gets defensive when anyone bad-mouths the books. He said they have turned non-readers onto reading and serve as a "gateway drug" to more complex children's books like the Harry Potter series.

Dav Pilkey

Captain Underpants creator Dav Pilkey has spun off his beloved character into several other series, including Dog Man. Here he is visiting CBC in Vancouver. (Charlie Cho/CBC)

"In terms of manners, the boys are actually good kids at heart, you know. They are questioning authority because the authority in question is questionable," he said.

"I think the movie promotes and the books do too, they promote creativity. I think that's the thing ultimately that is so powerful about this property in general is it encourages kids to you know, pick up a pencil. Make a story. Create something."

'It just didn't seem like good literature'

Soren said the movie is aimed at kids and those who are now in their 20s and 30s who read the books growing up. The initial Underpants book came out in 1997 and its still a big seller.

"People come looking for them," said Nadine King, a longtime bookseller at Woozles, a kids bookstore in Halifax.

She said it's especially popular with dads, but it took a long time for her to read one. She sheepishly admits to judging the book by its actual cover.

 

"It just didn't seem like good literature," she said. She was to surprised to find a good story line and well-developed characters. "I was being snooty and judgmental."

King too has noticed the book's impact on non-readers and hopes the film, stirs up even more interest. She's even considered dressing up as Captain Underpants for Halloween.

"I just haven't figured out how a 50-year-old woman would do that."