Public reaction to the death of SpongeBob Squarepants creator Stephen Hillenburg, who died from ALS last Monday, might have confused those unfamiliar with his most famous work. Here was a man being mourned across all ages and demographics, from the trades to Twitter, for creating … a cartoon made and marketed for children?

But this gets SpongeBob, Hillenburg ’s magnum opus, all wrong. At its best, SpongeBob was not simply a kids’ cartoon. From the beginning, Hillenburg brought to the show a unique tone and aesthetic that drew from his background in marine biology. He attended the show’s pitch meeting in a Hawaiian shirt. SpongeBob, the relentlessly upbeat, cleaning utensil-shaped main character, lives in a pineapple under the sea; Squidward, his grouchy next-door cephalopod, inhabits an Easter Island head. And the opening theme song is sung by a portrait of a (human) pirate. Though a veteran of Rocko’s Modern Life, another successful Nickelodeon program, Hillenburg had something all his own in mind from the start.

The result of this tonal intentionality was, at its peak, a delightful, offbeat, and sometimes surreal mix of childish humor for its purported target audience, reinforced by subtle or obscure (though never tasteless) comedy for older viewers. “Help Wanted,” the first episode, which premiered on May 1, 1999 (and which I viewed then as a five-year-old), is a good example of this. On the surface, it is a silly story about a fruit-residing sponge who decides to apply for a job as a fry cook at the Krusty Krab, a fast food restaurant run by a miserly crab in his underwater hometown of Bikini Bottom, a place populated by other anthropomorphic aquatic creatures. Some puerile humor ensues; entering the restaurant, SpongeBob trips on an errant nail and proceeds to spend about a minute tripping, falling, and bouncing around. It’s very silly stuff; slapstick taken just up to the point of absurdity.