Sentry / Hulk #1

From the Marvel Knights imprint comes this 2001 one-shot pairing two of Marvel's most formidable figures, with a cover by Bill Sienkiewicz that's genuinely haunting — a close, ghostly rendering of the Hulk's face emerging from a weathered, textured grey background, his green skin and hollow eyes rendered in an almost painterly, dissolving style. Paul Jenkins scripts the story, while Sienkiewicz's cover work alone signals something more psychologically complex than your typical slugfest.