The Koozebanian Phoob is a blue alien creature from the planet Koozebane who is interviewed by Kermit in episode 205 of The Muppet Show. The Phoob is a very unfortunate creature, because it is known as the most delicious creature on Koozebane. Luckily, the Phoob has hit upon a survival strategy -- it evolves very quickly into whatever is nearby. The sketch ends with the Phoob "evolving" into a clone of Kermit, causing the two Kermits to fight over which is the real one.
While episode 205 is the Phoob's introduction, he was previously seen in the audience during the Talk Spot in episode 119 and Fozzie's Monologue in episode 122. He appeared in the audience during episode 208, the At the Dance sketch of episode 311, and in episode 422 during "Green Door".
The blue version of the Phoob can be seen in one of the windows at the port in Muppet Treasure Island. This version also appears in The Muppets Go to the Movies, and both versions can be seen on background monitors on The Jim Henson Hour.
Both versions can be spotted in the "Waste Deep" and "War Room" PSA's for Better World Society.
The green version of the Phoob has most recently been featured walking backstage as Rowlf plays the piano after the "Bang, Boom, Splat and Pow" sketch in "Kermit's Story," the first in Roger Langridge's four-issue run of The Muppet Show Comic Book.