As a kid, my two favorite things in Mad magazine were the Fold-In and Spy vs Spy (which I pronounced "spyvisspy"). It was a wordless one-page comic about two oddly pointy faced spies, one dressed in black and the other dressed in white. Other than their different colored outfits, they behaved identically. They hated each other and created elaborate Rube Goldberg type machines to try to kill each other. Sometimes their machines worked, often, they'd backfire. They were tricky but usually too clever for their own good.
Atlas Obscura has an excellent article about Antonio Prohías, the creator of Spy vs Spy.
In New York, Prohías took work in a factory during the day, while working up his illustration portfolio at night. Taking inspiration from his supposed spy status, Prohías altered the look of El Hombre Siniestro, and gave him a counterpart, creating what we now know as Spy vs. Spy. In 1960, just months after moving to the city, Prohías, along with his daughter Marta who acted as an interpreter, walked unannounced into the offices of MAD Magazine. The editors were skeptical of the artist, but his silly spy gags won them over, and he had sold three of the strips to the magazine before leaving that day.
Spy Vs Spy: An Explosive Celebration, by Antonio Prohías and Peter Kuper, is an excellent book about Spy Vs Spy, with lots of sample strips.