The Voodoo Master

I agree, Agent T, that Dr. Rodil Mocquino is the best arch villain in the series.  And this is truly one of the iconic covers not only in the magazines run but of any various publications down through the decades.  Pretty impressive when one knows the time constraints that faced the illustrators back in the day vs. the later illustrators who had far more time to conceptualize book covers or even comic book covers.  If you haven't read this one (and shame on you if you haven't) then check out this review to whet your appetite and get you running to the reprint sitting on your bookshelf.