'SpongeBob SquarePants' creator Stephen Hillenburg is dead at age 57

It's a sad day for the residents of Bikini Bottom and fans around the world. "SpongeBob SquarePants" creator Stephen Hillenburg has died at age 57.

"We are sad to share the news of the passing of Stephen Hillenburg," read a message posted on Nickelodeon's Twitter and Instagram on Tuesday. "Today, we were observing a moment of silence to honor his life and work."

Hillenburg revealed in March 2017 that he had been diagnosed with amyotrophic lateral sclerosis, also known as Lou Gehrig's disease.

Oklahoma-born Hillenburg earned a degree in marine biology and first developed the ocean-dwelling comic characters as a tool for teaching students when he was an instructor at California's Orange County Marina Institute. He soon returned to college to study animation and first joined Nickelodeon in the mid-1990s to work on the animated show "Rocko's Modern Life."

During his time at Nickelodeon, Hillenburg further developed the ocean-dwelling characters into those we've come to know in "SpongeBob SquarePants." The animated series debuted on Nickelodeon in 1999 with the star character SpongeBob, and his neighbors Squidward Tentacles, Patrick Star, Mr. Krabs, Gary the Snail and many others. "SpongeBob SquarePants has aired ever since, even after Hillenburg left the show as executive producer.

Hillenburg also co-wrote and directed the 2004 hit theatrical release "The SpongeBob SquarePants Movie" and co-wrote its 2014 sequel, "The SpongeBob Movie: Sponge Out of Water." The show itself has become an industry unto itself through merchandising, music releases, video games, comics, theme park rides and even a Tony award-winning musical.