Mack is a member of the Smithy Gang and one of Smithy's lieutenants. He appears in the game Super Mario RPG: Legend of the Seven Stars. Mack is in command of an army of Shysters, pogo-stick riding Shy Guys. Mack also wields powerful fire magic. With his army of soldiers, Mack attacked the Mushroom Kingdom and occupied it. Mario, conveniently, was in Bandit's Way with Mallow, chasing down the thief Croco. Mack allowed his Shysters to overrun the town, causing chaos as they wished. Along with Bowyer, Yaridovich, and the Axem Rangers, Mack's inspiration was a weapon, in this case, a knife.
When Mario and Mallow returned to town, they were shocked by the sudden appearance of the Shysters. Together, they rescued townspeople and fought to the throne room of the castle, where they confronted Mack and his Shysters.
Mack is accompanied by a quartet of Shysters. The five use melee until Mario and Mallow defeat the Shysters. At this point, Mack will attack with fire magic. After a while, the Shysters return and Mack will leap into the air. All four Bodyguards must be defeated for the knife creature to return. After a few successful cycles, Mario and Mallow prevail, acquiring the first Star Piece. Following Mack's defeat, the two remaining Shysters left to inform Smithy of Mack's destruction. The duo then set out to seek counsel with Frogfucius, Mallow's grandfather.
Mack would return in Smithy's Factory, in the form of a gray mass-produced copy of the original.
Mack is a red-colored, roundish figure who holds onto a pair of handles on top of a giant knife with floating eyes (or maybe the knife itself), thereby riding the knife much as Shysters and their derivatives ride on pogo sticks. When attacking, Mack shakes his head.