Like another twisted madman on this list, The Jackal of the underworld was obsessed with ancient Egypt, in the Jackals case specifically; he was fascinated by their mythology. Dressing himself up like the ancient Egyptian God of the underworld (and not at all unlike a Jaffa from Stargate), The Jackal of the Underworld (in reality a man identified only as Gibson) adopted the personality of a wrathful Anubis. As if that wasnt bat-shit crazy enough, the mad motherfungler took advantage of Gotham Citys extensive underground cave network in order to commit his crimes, using the underworld both literally and figuratively, to his advantage. Once apprehended by Batman and Robin, he vanished from the pages of DC comics and was never seen again. Gibosons first (and last) appearance was published in 1958 and it hasnt been re-printed since (at least, not anywhere that I can find). The idea of a mythology-obsessed villain taking advantage of subterranean Gotham is simply too good not to be used again somewhere. It might work better if Gibson adapted his persona to include other underworld Gods and figures (gaining a three-headed dog named Cerberus for example and taking his costume cues from different deities, Calendar Man style). There is a potential to have some real fun with the character, so I hope somebody at DC 'digs him up' eventually.