Stephen Hillenburg, the creator of “SpongeBob SquarePants,” died on Monday, November 26, 2018. He was 57 years old. The cause of death was Amyotrophic Lateral Sclerosis, or ALS, a progressive neurodegenerative disease that affects the nerve cells in the brain and spinal cord and results in a loss of muscle strength and control.

Hillenburg originally began his time at Nickelodean with “Rocko’s Modern Life” in the mid 1990’s, but his magna opus “SpongeBob” had roots farther back in his past. Hillenburg was a marine biology teacher at the Orange County Marine Institute, now the Ocean Institute, in Dana Point, California. While working there, he wrote and illustrated stories to use as teaching tools. These would later become the various citizens of Bikini Bottom. In 1987, he went back to school to pursue a degree in Experimental Animation at the California Institute of Arts in Valencia. The year he graduated, he won the Best Animated Concept Award at the Ottawa International Animation Festival for his short “Wormholes.”

“SpongeBob,” Hillenburg’s best known creation, first aired on May 1, 1999. After the success of that first episode, the series commenced its full run on July 17 of the same year. The show has currently aired nearly 250 episodes and been on TV for almost 20 years. It has been dubbed or subtitled in over 60 languages, including Urdu and Maori, and earned a variety of awards such as U.S. and British Emmy Awards, Annie Awards and ASACP Awards.

“We are incredibly saddened by the news that Steve Hillenburg has passed away following a battle with ALS,” Nickelodeon said in a statement. “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.”

Hillenburg is survived by his wife, Karen; his son, Clay; his mother, Nancy; his brother, Brian; his sister-in-law, Isabel; his nieces, Emma and Hazel, as well as a tie-wearing sponge and his friends, the varied and quirky sea creatures that continue to inhabit Bikini Bottom.