Caroll Spinney, the puppeteer who brought to life beloved Sesame Street characters for almost fifty years, has died at the age of 85. The cause of his death was attributed to dystonia, a movement disorder that causes involuntary muscle contractions.

Spinney’s death was announced today by the Sesame Workshop, which honored Spinney and his years of creativity and dedication to the show. “Caroll was an artistic genius whose kind and loving view of the world helped shape and define Sesame Street from its earliest days in 1969 through five decades, and his legacy here at Sesame Workshop and in the cultural firmament will be unending.”

Big Bird and Oscar the Grouch are beloved characters from the children’s educational program, and have appeared everywhere from the Hollywood Walk of Fame to CNN with Anderson Cooper to NPR’s Tiny Desk Concert. Spinney often talked about his personal connection to the character of Big Bird, a curious six-year-old canary that lives on Sesame Street. “I think most people completely forget what it was like being a kid by the time they grow up,” he told The New York Times in 1982. “But I never got over it. It was almost a problem for me, in fact, trying to grow up enough, even when I went into the Air Force.”

Fans of Sesame Street, many of whom grew up with Spinney’s characters their whole lives, expressed their grief and gratitude for Spinney’s work.

Rest In Peace, Carol Spinney. Thank you for the kindness, the laughs, and the joy. pic.twitter.com/xIPEjFbUfO

— David Gallaher (@DavidGallaher) December 8, 2019

Thank you, Caroll. ❤️ pic.twitter.com/1xhL3Bwr9j

— 🎄Muppet History 🕎 (@HistoryMuppet) December 8, 2019

The creators behind Sesame Street also expressed their grief, including co-founder Joan Ganz Cooney, who stated, “Caroll Spinney’s contributions to Sesame Street are countless. He not only gave us Big Bird and Oscar the Grouch, he gave so much of himself as well. We at Sesame Workshop mourn his passing and feel an immense gratitude for all he has given to Sesame Street and to children around the world.”

Spinney passed away in his home in Connecticut earlier today. He is survived by his wife, Debra, as well as several children and grandchildren. No memorial plans have been announced. Sesame Street produced a tribute to Spinney after he stepped down from his acting role last year; you can watch the tribute below.