There Is No Justice League
Killer Croc’s backstory explains that he was born with a condition resembling epidermolytic hyperkeratosis, a disfiguring skin disorder. However, it is actually a form of regressive atavism, meaning that he has inherited traits of ancestral species of the human race such as reptiles. This condition has been augmented by the presence of a metagene. Consequently, he has several extraordinary physical abilities relating to his endurance, strength, and speed.
His skin is hardened to the degree that it is nearly impenetrable to ordinary forms of abrasion including high caliber weapons fired from a distance. He possesses a degree of super strength; for example, he was able to tear a bank vault door off of its hinges with minimal effort. He has demonstrated regenerative powers allowing him to heal and restore lost limbs and teeth. He possesses superhuman reflexes and speed, especially while he is moving underwater. Killer Croc also has an enhanced sense of smell. Once he has become familiar with a person’s scent he can track them from miles away. As his appearance and personality has grown more and more bestial, his misanthropy has increased dramatically. He is jealous and hateful of “normal” people and often lashes out violently without provocation.
His real name is Waylon Jones, born with a form of atavism that imparted him with reptilian traits. His drunk aunt grew to hate her nephew’s hideous appearance and brutal behavior. While still an adolescent, his aunt abused him and bullied him by calling him names like “lizardboy” and “a reptilian freak”. Croc killed his aunt and became a criminal. After countless killings and biting off Aaron Cash’s hand, he faced off against Batman and the new Robin, who defeated him.