The cultural impact of SpongeBob SquarePants cannot be denied. From the many memes and gifs it generated, to the constantly quotable dialogue, to the characters who found their way into the hearts of children and adults the world over, the Nickelodeon cartoon series has been a cultural monument since its debut in 1999.

On Monday, November 28, 2018, the man who created it all died. As Variety reports, Stephen Hillenburg has passed at age 57 from ALS, a neurodegenerative disorder. The cartoonist and animator announced he was diagnosed with the disease last March.

Nickelodeon released a statement addressing the news of Hillenburg’s passing and his great contribution to their network:

“We are incredibly saddened by the news that Steve Hillenburg has passed away following a battle with ALS. He was a beloved friend and long-time creative partner to everyone at Nickelodeon, and our hearts go out to his entire family. Steve imbued ‘SpongeBob SquarePants’ with a unique sense of humor and innocence that has brought joy to generations of kids and families everywhere. 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.”

That optimism and love was felt in every moment of the series. Moments like this one spring instantly to mind with the news of Hillenburg’s untimely passing:

Hillenburg, a California native, attended the California Institute of Arts in 1987 to pursue a career in animation. After a few successful short films, he was hired by Nickelodeon to work on the cartoon series Rocko’s Modern Life. In 1994, he began developing the characters who would eventually populate Bikini Bottom in SpongeBob SquarePants, including the titular sponge, his best friend Patrick Star, rival neighbor Squidward Tentacles, and more.

SpongeBob SquarePants premiered in 1999 and still airs to this day (the series is in its twelfth season). It has inspired two spinoff movies–the first of which Hillenburg directed and the second of which he wrote–and a Broadway musical, which was nominated for 12 Tony awards. A third movie, The SpongeBob Movie: It’s a Wonderful Sponge, will be released in 2020.

Hillenburg will be remembered by his legion of fans, collaborators, and family–including wife Karen and son Clay–and the legacy of SpongeBob will go ever on.

Featured Image: Nickelodeon