"What's up, Doc?" speaker voiced by Mel Blanc

BUGSBUNNY

This wascally wabbit outsmarts Elmer Fudd with a Brooklyn accent and a carrot.

This clue references the famous catchphrase "What's up, Doc?" which is strongly associated with Bugs Bunny, the iconic Looney Tunes character. Mel Blanc was the original voice actor for Bugs Bunny, making the connection clear. The answer is simply the character's name written as one word, "BUGSBUNNY," without spaces.