Spoilers for Justice League #56 ahead!
One of the Justice League’s dumbest weaknesses, the Martian Manhunter’s fear of fire, turns out to be their saving grace in a fight against a fearsome foe. In Justice League #56, by writer Joshua Williamson (The Flash), artist Robson Rocha (Birds of Prey), inker Daniel Henriques (Supergirl) colorist Romulo Fajardo Jr (Legion of Super-Heroes), the Martian Manhunter and Hawkgirl must stop the evil Mindhunter - and the solution comes from a most unexpected place: the Manhunter’s fear of fire!
Despite his great power, which often rivals Superman, Martian Manhunter has a most common weakness: fire. This fear is the result of manipulation of the Martians by the Guardians of the Universe in the distant past; the Martians were once composed of fire - they used it to reproduce. When the evil Martians threatened the cosmos, the Guardians of the Universe take action and split the Martians into two species, the White and the Green, and gave them all a fear of fire. Many of the Martian Manhunter’s enemies have exploited this weakness, making him something of a liability, given how much more common fire is than Kryptonite. But they turn this weakness against the Mindhunter in a most spectacular fashion.
The Mindhunter is an evil Batman/Martian Manhunter hybrid from the Dark Multiverse. Part of the Batman Who Laughs' Dark Knights, he attacks the Martian Manhunter and attempts to absorb him. He then taunts Hawkgirl, goading her over her romantic feelings for the Manhunter. But in his hubris, Mindhunter neglected to account for the fire weakness, and Hawkgirl uses this to overpower him.
Martian Manhunter is not only super strong and can fly, but he can also shapeshift and has telepathic abilities. He is an excellent tactician as well as the heart and soul of the team. All this should make him a huge asset to the Justice League, and in many ways it does - he has been a member of just about every incarnation of the team. But fire is far more common than Kryptonite or magic, and his weakness to it can potentially hinder him in combat. Considering Mindhunter didn't account for this weakness, it was easy for Hawkgirl to overpower him.
What does all of this mean for the Martian Manhunter? Will this help him conquer his fear of fire? It is deeply ingrained into his species, so deep in fact that attempts to cure him of it in the past lasted only a short while at best. Whatever the case, fans get to see him finally use this weakness to his advantage.