Mac is a mantis shrimp mutant.
Mac was a lonely man who did not have that many friends so, he bought a pet cat which he loved very much, but one day, Scum Labs took his cat for testing. He did all he could but they took his cat and, to compensate, gave him a Scum Soda in exchange.
Later that night, he drank every last drop of the soda, and started mutating! He roared, but in the wreckage of his house he saw a picture of his cat. Infuriated, he then roared again and made his way to the city.
At full power he can do his universal punch.