Hello crossword solvers! Today let's find the answer to the clue Mack Sennett's Keystone ___ from the USA Today crossword. After we've gathered any other hints from the USA Today crossword puzzle and all possible helpful and relevant information from other sources, we are ready to solve the clue Mack Sennett's Keystone ___. The answer we found for the clue Mack Sennett's Keystone ___ is: