Super-Gorilla Grodd is a great fiend who provides an excellent contrast to the Manhunter from Mars, which is why his fans fought to keep him in the Vile Menagerie. Decades of identification as a Flash rogue are tough to shake off though, so it may be time to shake paws and shove off back to the cities of Central, Keystone or Gorilla. They're all closer to home than Middletown can ever be, although with an even split of 26 votes, he may yet be close enough.
Anthony Ivo debuted in 1960 as the villain in the third appearance of the Justice League of America. He was featured on an iconic cover involving the Founding Five JLA sealed in individual tubes as their powers were sapped and redistributed to the robot Amazo. Jacking with the League was a secondary concern for Ivo, who was really pursuing immortality. He found it, and as fate is wont to do, it turned out to be a disfiguring, maddening curse. That last sentence wasn't relevant to the Martian Manhunter though, as he wasn't around for Ivo's reappearances in 1966, 1971, 1974, and 1978. There, Ivo fought League incarnations that excluded J'Onzz, or engaged in solo action against Superman and the Flash.
What put Ivo on the Vile Menagerie radar was a three issue arc chronicling "The End of the Justice League of America." It literally wrapped up the first volume of that series, and saw rogue android duplicates of Ivo murder Vibe and Steel. Gypsy pretty much saved herself, but it was up to the Martian Manhunter to rescue Vixen and put a stop to Ivo's runaway creations. It remains one of the best unsung JLA stories ever, grim and gritty before that was passé, while clearing the decks for the comedy stylings of the International crew. There was a swell panel of the Alien Atlas screaming Ivo's name while busting down a door, but not much of a final confrontation, and Ivo went into limbo for most of the next decade. When he did turn up, he was oddly cordial with the JLA, even donating an island base the the Justice League Task Force.
Ivo's true return to villainy came when he teamed up with T.O. Morrow to create Tomorrow Woman to infiltrate and undermine the Magnificent Seven JLA. He's turned up a number of times since, usually as a throwaway old school mad scientist or as a +1 to his more famous creation, Amazo. While some of these later stories have involved the Martian Manhunter, none have had any serious implications for the Sleuth from Outer Space. There isn't any one hero who could ever lay claim to Ivo, and even his status as a JLA foe of note waxes and wanes. Amazo is typically portrayed as too powerful for the Martian Marvel to take on his own, while Ivo hasn't offered up any other inventions that could seriously task the Manhunter. My inclusion of Ivo in the earliest draft of the Vile Menagerie was another ignorant overreach, and although he was official declined re-admittance in this blog's incarnation, the guy has turned up in our March Madness contests. It's been nice having him as a guest and all, but it's probably best that we finally send him on his way.