Gamble attempted to sell the idea to a group of Eldorado Zone investors during their visit to the Casino Night Zone. The slimy lizard planned to build an army of Metal Mates with their backing, putting the Zone's Mobian builders out of work. However, the prototype Metal Mate suddenly short-circuited and began attacking everyone with its hammer. Gamble let slip that it wasn't meant to go haywire until after the sale, something that didn't escape Sonic the Hedgehog's notice. The hedgehog rushed to destroy the faulty Metal Mate, but was briefly interrupted by Charmy Bee, who he had to push out of the way of a hammer blow. Charmy repaid the favour by distracting the robot, prising a pickaxe into Metal Mate's seams. Sonic then finished it off with a Spin Attack.
However, all was not well, as Gamble revealed that the head's plutonium core was about to explode, putting them all in danger. Charmy grabbed the head and flew off before throwing it high into the sky. The head detonated well away from any people or structures.