Stephen Hillenburg, the creative powerhouse who brought SpongeBob SquarePants to the surface world, has died of ALS. He was 57.

Nickelodeon, which has long been home to the series, confirmed the news this morning.

???? We are sad to share the news of the passing of Stephen Hillenburg, the creator of SpongeBob SquarePants. Today, we are observing a moment of silence to honor his life and work. ???? — Nickelodeon (@Nickelodeon) November 27, 2018

A former marine biology teacher, Hillenburg was known for using his early cartoons to help illustrate lessons at California’s Orange County Marine Institute. Years later, that nautical nonsense would become the source material to one of the most successful animated series of all time.

He eventually transitioned into a career in animation, and from 1993 he wrote, directed, and lead creative elements of Nickelodeon’s madcap series Rocko’s Modern Life.

The weirdness of that show would go on to inform SpongeBob SquarePants. Hillenburg debuted SpongeBob in 1999 as its writer and producer, and the show eventually became a cultural touchstone for an entire generation of the cartoon-watching public.

Throughout its tenure on television screens, SpongeBob SquarePants introduced countless viewers to a unique visual style, memorable characters, and a brand of optimistic absurdism that went on to influence many of those who ingested the series as children or young adults.

Hillenburg is survived by his wife Karen Hillenburg and their son Clay.