Pouncival is Carbucketty's second name, they have the same personnality. When Cats opened on Broadway, Carbucketty's name was changer to Pouncival. The name Pouncival can be found in most productions (Brodaway, US Tours, Germany), Carbucketty appearing only in London-based productions. Vienna is the one and only production where the two kittens could be seen at the same time, and I don't know what was the difference between them. Strangely, Pouncival appears in the video even if the video is London based... but he wears the typical London Carbucketty costume.
Pouncival's costume is very different from Carbucketty's one. It is much darker, its colors beeing more dark grey, brown and black. The only remaining thing is a spot on his left eye.
Toronto 1985 - Michael Arnold
Hamburg April 1991 - Jimmy Jillebo
Hamburg December 1997 - Devon Tullock
US Tour V July 2001 - David A. Blonn
Denmark September 2002 - Jens Johansson