10 Best Superman: The Animated Series Episodes
5. "The Way Of All Flesh"
Superman's rogues' gallery is filled with tragic characters who were either thrown into villainy against their will or succumbed to their baser urges and took up a life of crime. "The Way Of All Flesh" introduces Metallo to the series, a villain who not only chose to become an evildoer, but did so for the sole purpose of trying to take down the Man of Steel.
The seventh episode of the first season shows how John Corben had himself completely remade with a heart of Kryptonite for the sole purpose of destroying the man who sent him to Stryker's Prison.
After Corben is freed from prison but found to be dying of a disease, Lex Luthor talks him into undergoing the transformation, which makes him invulnerable and incredibly strong, but unable to feel anything. He no longer feels pain, hunger, or even thirst. He attacks Superman, but eventually learns that his true enemy was Luthor all along.
Superman reveals that Luther's machinations sickened Corben who then sought the treatment that turned him into Metallo - an unfeeling monstrosity. When Metallo turns on Luthor, he nearly kills him, but is saved by Superman at the last moment. When Luthor gloats that Superman can't pin anything on him, he is reminded that the Last Son of Krypton isn't the one he should fear. The episode concludes with Metallo walking along the sea floor with revenge still clearly on his mind, and it's one of the best images the animated series ever conjured.