DC’s Batman inevitably found a way to exploit his greatest weakness.
Like all powerful beings, however, J’onn has an Achilles’ heel, which in his case turns out to be a severe vulnerability to fire. In addition to having a severe phobia to fire, exposure to fire causes him to lose focus and make it difficult for him to even maintain his physical form. As a result, when Batman came up with tactics to take down the JLA’s , he worked out a terrible way to neutralize J’onn.
In the JLA storyline “Tower of Babel,” Batman’s enemy Ra’s al Ghul discovered the Dark Knight’s secret plans to take down every member of the Justice League and decided to use it for his own ends. R’as actually sent his own daughter Talia to shoot the Martian Manhunter with a missile that coated J’onn’s skin in a layer of nanites. At first, J’onn seemed unharmed, but within seconds the nanites converted the outer layer of his skin into magnesium, causing him to burst into flames on exposure to air.
Strangely, this was almost identical to how Marvel Comics’ original superhero The Human Torch first manifested his powers. Although most fans are familiar with the Human Torch as a member of the Fantastic Four, the first Human Torch was an android who had the power to burst into flames whenever he came into with oxygen. As an artificial being, the Torch was unharmed by his flames and eventually learned how to control his fire powers – becoming an early superhero who fought alongside Captain America, Bucky, and the Sub-Mariner.
Unfortunately, the same could not be said about J’onn J’onzz who immediately panicked when flames erupted from his body. Crashing into a forest, the terrified Martian Manhunter ran amok, setting the wilderness on fire. Fortunately, the Flash and Wonder Woman were alerted to the disaster and tracked down the burning man, believing him to be a super villain. When they discovered this “Martian Torch” was actually their friend and teammate, they took J’onn back to JLA headquarters and were able to submerge him in fluids that prevented him from spontaneously combusting.
J’onn was fitted with an Atlantean suit of armor filled with fluid, granting him some mobility, although combat threatened to crack open his suit and set him on fire again. Fortunately, he was able to neutralize the nanites – but when he discovered Batman’s role in his condition, he was livid. Nevertheless, he also realizes that at one point, he also kept files on the JLA’s strengths and weaknesses (although he did not develop neutralizing battle tactics like Batman). Thus, when the Justice League votes on Batman’s expulsion from the team, J’onn votes to let him stay.
The Martian Manhunter and Batman were established as having a fairly close relationship in some continuities. Both are detectives and both often feel more comfortable operating from the shadows. Nonetheless, knowing that his friend was planning on turning him into a version of the Human Torch must have put a huge strain on J’onn’s relationship with Bruce Wayne. While he may understand why the Dark Knight felt the need to create such a contingency, the horror of having his teammate turn his worst fear against him must have been devastating.
