Killer Croc

Waylon Jones, better known under his alias Killer Croc, is a monstrous reptile humanoid who lives in Gotham City's sewers, attacking the people who come down there and eating them, chucking their bones into the waters. Waylon was born with a rare genetic disorder which gave him the physical characteristics of a crocodile. His birth was so unusual that it caused the death of his mother.

Waylon went to school where he was heavily bullied by the other students. When he was 10, he snapped and killed one of his bullies. Charged with murder, he was sent to a juvenile detention center for 1 month. By the time Waylon was 16, he had been arrested for robbery. Years later, Waylon found a way to make money. He joined a fight club where he wrestled alligators to the death, under the name 'Killer Croc'.

After this, Killer Croc went to Gotham City in hopes of joining the mob. He wore a disguise, a trench coat and hat, and took up jobs for crime bosses in Gotham, including the likes of Black Mask and The Penguin. The disturbances lead Batman to investigate, only for him to discover that what lay under the hat was a monstrous human crocodile. Killer Croc stopped being hired for jobs and eventually went down to the sewers, becoming one of the most dangerous adversaries Batman had ever faced.

However, his reputation was ruined when Bane showed up in town. Not only famous for breaking Batman's back, but Bane also seriously injured Killer Croc. Killer Croc was heavily beaten by Bane, and left for dead. Croc survived, however the damage had caused him to become a mindless monster, who eventually took to eating human flesh.