Action Comics #570

The cover of Action Comics #570 sets up a genuinely unsettling mystery: Superman, cape billowing, rushes forward alongside a wide-eyed young man — almost certainly Jimmy Olsen — while panicked civilians scatter on all sides, all of them fleeing the enormous, predatory shadow of an unknown figure looming behind them. Eduardo Barreto's cover art makes terrific use of negative space, letting that dark silhouette dominate the composition and give the question at the bottom — "Who Is Alter Ego?" — real menace. It's a smartly designed August 1985 issue that uses atmosphere over flash to pull you straight in.