Batman usually does well when pitted against immortal villains. Grant Morrison has had the Dark Knight face off against Dr. Hurt and Mr. Whisper, as well as the (potentially immortal) Lord Death Man, all to great sales and acclaim. More recently, Scott Snyder had Batman battle the seemingly ageless Court of Owls. Then of course, theres the effectively immortal Ras Al Ghul, another of Denny ONeils mad ideas. Theres just something about immortality and the Batman, and its gotten me to thinking about an old issue called The Secret of the waiting Graves. In this 1969 story, beautifully illustrated by Neal Adams, Bruce Wayne travels south of the border to Mexico in order to attend a party held by wealthy socialites Juan and Delores Muerto... Unbeknownst to Batman, Juan and his wife are criminals who have achieved immortality via the use of Sybil flowers. The flowers are a mysterious natural source of longevity (and precursor to the Lazarus Pit presumably they grow near or around the pits). Once discovered, the couple not only subject Batman to the wrath of their cursed flowerbed, but they also attack him with trained birds (yes, really). The flowers prove to be powerful hallucinogens, also causing madness (but hey, it was the 60s and Batman was getting drugged in every other issue, so he got past it). Of course, Batman escapes and the couple both die well-deserved deaths. As a creepy, undead reflection of Thomas and Martha Wayne, Los Muertos are sorely underused. I think the effect on Bruces psyche as he battles the wealthy Wayne-like socialites would be very interesting to see indeed. The potential for linking Sybil flowers with the Mexican drug trade is also glaringly obvious and the supernatural aspect of the characters makes for a neat twist too. As villains of a hundred years or more, there are possible links to be made with Dr. Hurt (in his guise as El Penitente), Jason Blood and Ras Al Ghul amongst a great many others. The couple have only ever appeared once, in the aforementioned adventure, but Id personally love to see them again.