The X-Men #38

From 1967 comes this action-packed chapter of Marvel's mutant team, its cover by Dan Adkins and John Romita pulling no punches: the massive, bare-torso Blob grapples directly with Cyclops and Angel at center stage, while Marvel Girl and other X-Men battle in the background — and a brooding Professor X looms large at the top. The cover boldly promises "The Blob and the Vanisher" as the twin threats behind a disaster called Doomsday, and a bonus feature, "The Origins of the X-Men," is teased in the corner box. Roy Thomas scripts and Don Heck illustrates what looks to be one of the team's most formidable challenges yet in "The Sinister Shadow of... Doomsday!