CNN and Mental Floss have a great article about the origins of 20 Muppet characters, detailing where they first appeared and who or what inspired them. I’ve been a fan of the Muppets for as long as I can remember, but there were a lot of things on the list I didn’t know.
Here’s an example:
Gonzo: What exactly is Gonzo? Nobody knows. Even Jim Henson had no particular species in mind. Over the course of "The Muppet Show," "Muppet Babies" and various Muppet movies, Gonzo has been referred to as a "Whatever", a "Weirdo" and an alien. Whatever he is, he first appeared on the scene in 1970’s The Great Santa Claus Switch. His name was Snarl the Cigar Box Frackle. In 1974, he showed up on a TV special for Herb Alpert & the Tijuana Brass. He became Gonzo the Great by the first season of The Muppet Show and developed his thing for Camilla the Chicken almost accidentally: During one episode where chickens were auditioning for the show, puppeteer Dave Goelz ad-libbed, "Don’t call us, we’ll call you… nice legs, though!" It was decided then and there that Gonzo would have a bizarre romantic interest in chickens.
Check out the entire list for the Surprising Stories Behind 20 Muppets