The Incredible Hulk (1966 cartoon)

Nuclear scientist Bruce Banner found his life turned completely upside down when he was supervising a test of his new gamma bomb. Seeing teenager Rick Jones loitering in the test site, Banner goes out to remove him. However contrary to his orders, his assistant Igor, who is actually a Soviet spy, allowed the bomb to detonate while Banner was exposed just as he put Rick in safety. Miraculously he somehow survives, but he has a new problem. Now whenever he undergoes stress, he transforms into the massive monster, the Hulk. Now he must fight either General "Thunderbolt" Ross of the US Air Force who obsessively hunts the creatures, or villains like the Leader, a mad scientist whose own exposure to gamma radiation made him a malevolent genius. (1)