Man-Bat

"Dear God. Is this what I have become? More animal than man. When will the surrender be complete?"

- Man-Bat

Dr. Kirk Langstrom, a scientist specializing in the study of bats, develops an extract intended to give humans a bat's sonar sense and tests the formula on himself because he is becoming deaf. The extract works, but it has a horrible side effect: it transforms him into a hideous man-sized bat. The serum also takes away his intelligence, so he goes on a mad rampage until Batman can find a way to reverse the effects.

Later, Langstrom takes the concoction again, and Man-Bat returns. He also coaxes his wife, Francine Langstrom, into drinking the serum, and she goes through the same transformation, becoming She-Bat. Together, they terrorize Gotham City until Batman can once again restore them.

On some occasions, Langstrom takes the serum and retains enough intelligence to work for the forces of good. During one of these periods he works with the detective Jason Bard. On another occasion, in Action Comics #600, Jimmy Olsen inadvertedly puts Superman into a cave occupied by Man-Bat to protect him from Kryptonite radiation that had reached Earth following the explosion of Krypton. Man-Bat calms the maddened Superman and then summons Hawkman, who helps Superman overcome the radiation.

Kirk and Francine have a daughter, Becky, and a son, Aaron. Because of the effects the serum had on Aaron's DNA, he is born with a deadly illness. Francine turns him into Man-Bat form to save his life. This occurred in issue three of the Man-Bat mini-series by Chuck Dixon.

Man-Bat is sighted in Alexander Luthor, Jr.'s Secret Society of Super Villains during the events of the 2005–2006 storyline "Infinite Crisis".

In the aftermath of that storyline, both Kirk and Francine are shown to be alive in the 2006 "One Year Later" storyline. In Batman #655 (September 2006), Talia al Ghul ties up and gags Francine, and then threatens to poison her if Kirk does not give her the Man-Bat formula. After Langstrom gives her the formula, she releases Francine as promised. Talia utilizes the mutagen to turn members of the League of Assassins into Man-Bats.

In Gotham Underground, Man-Bat is apprehended by the Suicide Squad. He is one of the villains seen in Salvation Run. Francine has appeared in Batman and the Outsiders, serving as the team's technical advisor, and her assistant Salah Miandad operates the "blank" OMAC drone known as ReMAC. In issue #10 of that series, Kirk appeared, seemingly healthy and also aiding Francine.

In the 2008 miniseries Final Crisis, Man-Bat has been turned into a Justifier and was shown attacking Switzerland's Checkmate Headquarters.

During the 2009 "Battle for the Cowl" storyline, following Batman's death, Kirk is haunted by nightmares of becoming Man-Bat and killing his wife. When Francine disappears, he takes the serum and tries to follow her. After an altercation with the Outsiders, he returns to his human form and is captured by Doctor Phosphorus, who reveals the serum is not necessary to trigger the change. Kirk discovers that Phosphorus has also captured Francine, and becomes Man-Bat to save her.

During the 2009–2010 "Blackest Night" storyline, Francine tracks down Kirk (as Man-Bat), having created a cure, and revealed that Kirk's next transformation would be permanent if he did not drink it. Kirk attempts to take the cure, but his Man-Bat persona will not let him. Just as Kirk is about to drink it, Francine is wounded in the crossfire of the battle between Black Lantern Solomon Grundy and Bizarro (the latter of whom is already at the scene, trying to prevent Kirk from taking the cure). Distraught at Francine's injuries, Kirk transforms into Man-Bat, seemingly permanently

In Collision following Red Robin's actions against Ra's al Ghul, the latter attempts to murder people related to the Bat-Family. Man-Bat, following Red Robin's orders, took part protecting Julie Madison, a former lover of Bruce Wayne, against Ra's al Ghul's ninja.