The Zoocus was Jim Henson's proposal for a variety show with Muppets sometime around 1960, combining the words "zoo" and "circus". Sketches exist for a possible set layout consisting of walls with colonnades much like those seen later in the second season opening of The Muppet Show. Illustrations suggest that human guest stars would interact with the puppets in this way so that the puppeteers would not be seen. Henson would later decide to use the frame of the television to do this.
Some character designs exist for the television series concept. One, a philospher, played a role not unlike the later character, The Mighty Favog from the "Land of Gorch" segments on Saturday Night Live. He's described by Jim as often misquoting, answering inappropriately and not knowing anything particularly practical. Another character was being developed from two different angles: Mr. Ripple would have either been a roundish-looking dinosaur-like creature, or an octopus-like puppet with four tentacled arms. Carburetor Jones was designed as a motorcyle hipster always on the go and speaking mostly of motors and engines, while a fourth character, a crew-cut cat who spoke in jazzy riffs, appeared to be a hipster of the musical nightclub sort.
Sketches and further details can be found in the book Jim Henson's Designs and Doodles.