I recently linked to a piece by Art Spiegelman on Bernard Krigstein. In it he mentions a story that Krigstein did:

What reputation he has rests on a handful of short stories he illustrated in 1954 and 1955 for EC comics (the folks who brought you Tales from the Crypt and Mad), but one of those stories, "Master Race," was an accomplishment of the highest order—a masterpiece.

Thanks to Robot Wisdom, here is the story:

Master Race.