Aquaman #57

The cover tagline says it all — "The Sea Has a New Master!" — and the underwater tableau by Eric Battle and Norm Rapmund makes that threat feel immediate: Aquaman is tangled in writhing green tendrils at the bottom of the image, his expression strained as schools of dark fish swarm above him. Descending toward him is a savage, clawed Piranha-Man, all gnashing teeth and menace, while the deep ocean seascape of rock and kelp closes in around the King of Atlantis. It's a striking 1999 DC snapshot of Aquaman at a genuine disadvantage, with Erik Larsen and Chris Eliopoulos steering the series into gloriously dangerous waters.