Jerry Nelson, the puppeteer behind Sesame Street's beloved Count von Count, died Thursday at the age of 78. The cause of death was unspecified. At the 40th anniversary of Sesame Street, Nelson wrote:

"Chance, dumb luck or destiny? Who knows the controlling force that chooses where and how we find our lives manifest? I can only say I have traveled through the breathtaking up and down melody of a lifetime that, I studied and trained for, wandered the paths of least resistance (following my water nature) to, and that I am either blessed and one of the luckiest bozos walking this planet or both."

While Nelson's most famous character was the Count, he also Gobo Fraggle on Fraggle Rock and The Muppet Show's Sgt. Floyd Pepper of the Electric Mayhem band; Dr. Julius Strangepork from "Pigs in Space;" Kermit the Frog's nephew Robin; and Gonzo's girlfriend Camilla the Chicken.

Nelson had been with Sesame Street since the 1970s, and worked there through 2004, when he retired. According to CBC, he continued doing the voice of the Count until his death.

As Count von Count:

Here he is on the left, as Dr. Stangepork, in "Pigs In Space":

Here he is as Robin, Kermit's nephew, helping out with a Beatles cover: