Stu Rosen, best known for his work as the creator of “Dusty’s Treehouse,” died Sunday after a battle with cancer, his cousin Donna Siegel confirmed on Facebook. He was 80.

“This is a very sad day for my family and I. My wonderful, colorful, fantastic cousin, Stu Rosen died this morning,” she wrote. “My heart is broken and I’m sure anyone who has ever met him feels the same way. What a character he was… I will always have a special place in my heart for this fabulous man. Rest in peace my special cousin.”

Rosen first entered the entertainment industry as a production assistant for KCET, before pitching “Dusty’s Treehouse” to CBS in 1965. He would end up working on the show for ten years, starring as the eponymous Dusty himself alongside a number of puppet animal costars. “Dusty’s Treehouse” would also go on to win eight Emmys and a 1973 Peabody Award for its kid-friendly coverage of topics such as good health habits, school performances and music before re-airing on Nickelodeon in the 1980s.

Outside of “Dusty’s Treehouse,” Rosen worked as the casting director for the “Teenage Mutant Ninja Turtles” and as the voice director for a number of popular cartoon shows including “Captain N: The Game Master,” “Defenders of the Earth,” “Fraggle Rock,” “Mask” and “My Little Pony: The Movie.”