Stephen Hillenburg died Monday of Lou Gehrig’s disease, also known as ALS. He was 57.

“Steve imbued SpongeBob SquarePants with a unique sense of humor and innocence that has brought joy to generations of kids and families everywhere,” Nickelodeon said in a statement. “His utterly original characters and the world of Bikini Bottom will long stand as a reminder of the value of optimism, friendship and the limitless power of imagination.”

Hillenburg graduated from Humboldt State University in 1984 with a bachelor’s degree in Natural Resource Planning and Interpretation, with an emphasis on marine resources. He then became a marine biology teacher at the Orange County Marine Institute (now the Ocean Institute) in Dana Point, California. Hillenburg’s deep interest in marine life combined with his artistic talent and love of the sea and its creatures, led him to write and illustrate stories as teaching tools with characters that would later become the denizens of SpongeBob’s home, Bikini Bottom.

A good-natured pineapple-dwelling yellow sponge and a motley crew of sea creatures was not initially viewed as an inevitable hit. On its 10-year anniversary in 2009, Brown Johnson, then the vice president of animation for Nickelodeon, told NPR’s Elizabeth Blair about some early conversations at the channel.

“Certain parts of the business at Nickelodeon were like, ‘Oh no. It’ll never be successful. It’s about a sponge. What’s that? It’s yellow. That’s a bad color,’ ” she said.

Now, the show has been on since 1999. It’s spawned two movies – 2004’s The SpongeBob SquarePants Movie and 2015’s The SpongeBob Movie: Sponge Out of Water – and a Broadway show.

Its nearly 250 episodes have won four Emmy Awards and led to an endless line of merchandise to rival any other pop cultural phenomenon of the 2000s.

And it has profound global reach. According to Nickelodeon, it’s been translated into more than 60 languages. Images of the smiling yellow sponge are seen around the world.

In a 2004 interview with Fresh Air, Tom Kenny, the longtime voice of SpongeBob, describes Hillenburg’s dynamic style in the studio.

“Hillenburg definitely is the big kahuna and, a lot of times, just has every vocal nuance and eye blink and twitch mapped out to the nanosecond in his mind. And then other times, he’ll just take you off the leash and go, `You know, I don’t know where this is going. Just take it where it feels funny,’ ” said Kenny.

As he put it, some days working on the show was like doing math – other days, jazz.

Earlier this year, Kenny paid tribute to Hillenburg while presenting him with an award at the Daytime Emmy Awards. He lauded the wide and enduring appeal of the show: “I fell in love immediately and it seems like some other people did too.”

Hillenburg is survived by his wife of 20 years Karen Hillenburg, son Clay, mother Nancy Hillenburg, and a brother, Brian Kelly Hillenburg.

Rest in peace, Stephen Hillenburg.
You won’t be forgotten.