Jim Henson was determined to use the larger budget of a feature film to push the technological limits and capabilities of puppetry. One of the most difficult feats (and one that appears deceptively easy on-screen) was making Kermit ride a bicycle.
When Animal accidentally eats Dr. Bunsen Honeydew's Insta-Grow pills, he memorably balloons through the roof. Jim Henson refused to use a normal puppet on a miniature set to accomplish this effect, so his crew had to construct a gigantic Animal head that measured sixty feet.
Jim Henson spent an entire day in a 50-gallon steel drum submerged in a pond for the opening scene of Kermit the Frog in the swamp.
The closing reprise of "Rainbow Connection" featured a crowd of more than 250 Muppet characters, virtually every Muppet that had been created up to that point in time. According to Jim Henson archivist Karen Falk: "One hundred thirty-seven puppeteers were enlisted from the Puppeteers of America (along with the regular Muppet performers) to perform every Muppet extant. Prior to the day-long filming of the shot, Henson gave the enthusiastic participants a lesson in the art of cinematic puppetry. Amazingly, it did take just one day." The Muppet Show Fan Club newsletter answered the question of "How did they do it?" The response was "There are 250 puppets in the last shot of the film, and they're all moving. How? One hundred fifty puppeteers in a six foot deep, 17-foot wide pit, that's how. They were recruited through the Los Angeles Guild of The Puppeteers of America and almost every puppeteer west of the Rockies reported for pit duty."
Edgar Bergen died shortly after his scene was shot in 1978. It held particular meaning for Jim Henson, who cited, on many occasions, how Bergen and his wooden sidekick, Charlie McCarthy, influenced his interest in puppetry. The end credits include a dedication to Bergen.
Caroll Spinney: Big Bird tells Kermit and Fozzie that he's going to New York City to break into public television, a reference to Sesamo apriti (1969), the television show that popularized The Muppets.
Frank Oz: Wearing motorcycle gear at the El Sleezo Café. He's the thug who wrestles with Fozzie (one of his main roles).
James Frawley: El Sleezo Cafe waiter. "Maybe he should try Hare Krishna." / "Good grief, it's a running gag."