A veteran fan reading the banner “Is This the Beginning of the End of the Doom Patrol!” on the cover of The Doom Patrol # 121 (Sep.-Oct., 1968) would have probably written it off as hype, a come-on to entice him into buying the comic. But once he opened it to the splash page, he would have known that something genuinely unprecedented was going on. Instead of the usual action-packed scene of Our H…