Premise: John Powers Severin (December 26, 1921 – February 12, 2012) was an American comics artist noted for his distinctive work with EC Comics, primarily on the war comics "Two-Fisted Tales" and "Frontline Combat"; for Marvel Comics, especially its war and Western comics; and for his 45-year stint with the satiric magazine "Cracked". He was one of the founding cartoonists of "Mad" in 1952.
Hypothesis: John Powers Severin was not the only founding cartoonist of "Mad".