Who is Inspector Gadget's nemesis?

While there have been numerous iterations in the decades since, and in fact the franchise is still chugging along, we're not friends unless you agree that the original Inspector Gadget cartoon is the one and only version worth giving a damn about.

Part Get Smart, part sci-fi, and full-on '80s, the original series ran from 1983 to 1985, and like many cartoons of the time enjoyed longevity in syndication. With the (unknowing) help of his niece Penny and her dog Brain, plus any cool gadget you can think of that would help a cyborg defeat bad guys, Inspector Gadget is both bumbling and brilliant.

And you've got to feel for Chief Quimby, who you'd think would stop making messages that self-destruct at some point. Is the info he gives Gadget really that sensitive?

Gadget defends the citizens of Metro City from the evil M.A.D. organization. But most of all, from the leader of M.A.D., who also happens to be his arch-nemesis. Who is that, anyway?