S1·E21 The Ultimate Weapon

Gadget is sent to investigate why Dr. Claw is holding a contest with a $1,000,000 prize for the owner of the world's stinkiest animal. Meanwhile, Penny has given the Gadgetinis an experimental digestive systems so they can eat and turn food into electricity. They quickly become addicted to eating and try everything which causes the digestive systems to overload and emit noxious odors so they win the contest. Gadget is happy to get the check but the contest is a front for a MAD plot. The winning animal is to be squished and their concentrated stink extract used to arm an orbiting stink bomb which will cover the world with a foul-smelling stench. Then, MAD will sell the scent neutralizer their chemists created for a fortune since everyone in the world will be a customer. Since the Gadgetinis won, they're taken to the squashing machine and Gadget's too happy to have won $1,000,000 to interfere so it's up to Penny to save the day.