Possible Clues:

• As filler, shortly check on old comedian
• Star of Duck Soup (1933)
• Hugo or Charlie’s eccentric comic brother
• The Marx brother with spectacles and a cigar
• Nickname by which Julius Marx was better known
• Mustachioed Marx brother
• The third of the Marx brothers
• Try to catch rook that hurt amusing brother
• Crab and duck for amusing brother
• Marx's work inspiring leader of revolution that's uncomfortable