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Muppet Time Travel (also known as Muppet Time Machine) was mentioned in a Jim Henson Company press release in 2001. A script was written by John Derevlany. The concept involved Animal stumbling into one of Dr. Honeydew's time-traveling appliances, and going back to the Stone Age, where he inadvertently becomes evolution's missing link.
Finding themselves living in a world of humans descended from Animal, including the wild Postman Joe, Kermit and friends must go back in time to fix things.