What’s the difference between the stars of the two biggest movies opening this weekend? One is an inanimate object (National Treasure’s Nicolas Cage) and the other is as lively a being as the big screen has ever seen. That being, of course, is none other than SpongeBob SquarePants, and Stephen Hillenburg is the man behind the invertebrate.  The creator, director and screenwriter of both the series and The SpongeBob SquarePants Movie, Hillenburg shares the enthusiasm and catholicism of his animated offspring: he aims to make the show appealing to all sorts of audiences.

Still, SpongeBob SquarePants belongs to a different breed of contemporary cartoon than Family Guy or The Simpsons. To begin with, its tone can’t exactly be described as one of social commentary. Its characters inhabit an underwater world that is in no meaningful way an avatar of our own. Anthropomorphic sea creatures might lie only a few steps beyond an alcoholic talking dog, but those steps cover significant distance. The only thing the three shows share is armies of loyal viewers that span the spectrum from toddlers to their parents to college students.

Without the satiric edge of its humanocentric brethren, how does the SpongeBob empire manage to captivate 20somethings even while sober? Hillenburg’s characterization of the show suggests an answer.

“SpongeBob represents idiocy,” he theorizes. “He is dumb.  Patrick is dumb.  Mr. Krabs is greedy.  Squidward is a snob and vain.” It is a simplisitic but recognizable world that is fun, original and comforting. And terribly funny.

Translating this world of archetypal characters from the small screen to the big presented a unique set of challenges for Hillenburg. He admits that his “experience was really writing 11-minute shows, not even 22-minute.”

In the series, they tried “to keep it very simple and do storylines where there are not a lot of B-plot, but when you do a 75-minute movie that becomes difficult,” says Hillenburg. “We did the movie [because] we wanted to tackle a larger story with greater stakes, [one] that had an arc for SpongeBob, something where he actually goes through growth in the movie.”

The movie also allowed Hillenburg to answer a nagging question: “What would happen if the characters were to encounter our world?”

This motivation, that SpongeBob and friends should learn what life is like up where they play all day in the sun, led the writers to consider combining animation with live action, and to write David Hasselhoff into the script.

“We basically wrote him into the story without asking him,” Hillenburg says, “which is a really dangerous thing to do when you are under a tight deadline. But we needed a person that we associate with the ocean like Jacques Cousteau or something and Hasselhoff became the person to represent the quintessential lifeguard. So, crossing our fingers, I just called.”

Fortunately for Hillenburg (and for the star potential of the intrepid square-pantsed man-child of Bikini Bottom), Hasselhoff was excited by the opportunity. “He didn’t even think about it,” the director recalls, because “he has kids and they love the show.”

Scarlett Johansson agreed to be the voice of a new character, Mindy the Mermaid, with equal enthusiasm. “I was just shocked because her performance in Lost in Translation was just amazing,” Hillenburg says. “So we just really lucked out.”

Hasselhoff and Johansson’s cameos may seem like in-jokes for the adult audience, but Hillenburg maintains that the writers don’t push anything that goes beyond its ostensible target audience. They may write for themselves, but they always ask whether something is too adult.

“It is a kid’s network and a kid’s movie,” he emphasizes. But “generally we try not to write down to kids. We really just try to write a visual, character-driven cartoon that has a lot of slapstick and really appeals to us. I guess we are just lucky that other adults find that amusing, too.”

Hillenburg has experience writing for broad audiences; he worked for years on the staff of Rocko’s Modern Life. He may not have been the creator (which perhaps explains its less-overwhelming success), but he “learned a great deal about writing and producing animation for TV, and a lot of people came off of Rocko that work on SpongeBob,” he noted. The most interesting holdover, perhaps, is actor Tom Kenny, the voice of both SpongeBob himself and Rocko’s sidekick Heffer Wolfe.

When Hillenburg did finally come to control the creative reins, it seems that his education influenced the direction he would take; he studied Marine Resource Planning and Interpretation in college and later taught at the Ocean Institute in Dana Point, Calif.

While working on Rocko he realized that “if I were to do an animal show there is all this stuff that I am interested in that really no one has ever animated. Things like plankton.”

He adds, “A lot of things came out of my interest in marine biology, like the fact that there are scallops that fly in the air and in SpongeBob’s world scallops swim the same way in the ocean.”

“So that is just an example where it kind of informs the show,” he says, “but we are more about just making things humorous.”

Hillenburg thinks that it is this pervasive humor which really attracts college-aged viewers. He is more surprised that the audience extends beyond them.  

“You have to imagine you write a show about a sponge and you think that maybe a few people will think it is funny, some college students, but it takes off. It is truly shocking,” he says. “To the point where it is bizarre.”

—Staff writer Alexandra B. Moss can be reached at abmoss@fas.harvard.edu.