Superman #310

Superman staggers under a blast of green Kryptonite energy as Metallo — grinning and menacing in a brown suit — unleashes the power of his infamous artificial heart, with the cover's dialogue making clear that the Man of Steel may have been gravely mistaken in assuming all Kryptonite was gone for good. The dynamic cover art by José Luis García-López and Bob Oksner captures the raw threat Metallo poses with real urgency, framing this 1977 issue around a villain who carries the one weapon Superman simply cannot ignore. With interior work by writer Martin Pasko and artist Curt Swan, "The Man with the Kryptonite Heart" looks to be a tense, character-driven confrontation between two figures whose destinies are literally intertwined by green radiation.