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 could be seen in the audience during Talk Spot in episode 119 and Fozzie's Monologue in episode 122. In episode 208 he appeared in the audience. The Phoob also makes an appearnce in the At the Dance skecth of episode 311.
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" PSA 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.