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Itchy is Grungetta's pet Rottendoodle -- a grouchy dog breed. Grungetta shows off her dog to Oscar the Grouch in episode 4127, and encourages him to adopt his own Rottendoodle.

Unlike Oscar's dog, Cranky, Itchy is a properly grouchy pet. He's dirty, and he doesn't do anything that Grungetta tells him to do.