Grubber

The oddest member of the Gangreen Gang. Like the original, Grubber ordinarily is unable to speak properly. Rather than blowing raspberries, Grubber instead makes an odd grunt. His father resembles him and has the same speech pattern. Possibly in reference to the original, Grubber can change his form to match anyone he wants. Unlike Sedusa, who has a similar ability, Grubber's disguise is never complete. His green skin, eyes, and tongue are still visible through his disguise. Oddly enough, with the exception of the Powerpuff Girls Z, no one can see through his disguise.

(Source: AniDB)