Killer Croc

ウェイロン・ジョーンズ / キラークロック

In Croc's early appearances — a Detective Comics story arc that ended with Jason Todd taking on the role of Robin — he was shown as an unnamed, shadowy figure in a trenchcoat. A ruthless criminal aiming to become Gotham City's crime boss, Croc operates behind the scenes, using tactics like sniping to eliminate rival criminals. He briefly unites a small army of Batman villains under his command. When Batman finally confronts his mysterious adversary, the villain is revealed to possess a massive physique and a reptilian appearance. It is then disclosed that his real name is Waylon Jones, born with a form of atavism that gave him reptilian traits. His parents came to loathe their child's hideous appearance and brutal behavior. While still an adolescent, his father abandoned him in the wilderness. Croc survived, becoming a career criminal. Batman and the new Robin defeat him after a desperate battle.
In these original, pre-crisis appearances, he resembled a powerfully built man covered entirely in green scales, but was still basically human in his facial proportions and build. Over the years, writers have discarded the original conception of Croc as a crime lord; for instance, Killer Croc was originally depicted as gunning down Jason Todd's parents (this was later retconned to make Two-Face their murderer). His appearance and personality have become increasingly bestial, explained in the comics as his disease slowly robbing him of all identifiable human traits. In his most recent appearances, he has an elongated snout and tail.
Killer Croc was originally an inmate at Arkham Asylum, born with a rare skin disorder that deformed him to look like a crocodile. He became an experiment subject for Jonathan Crane's (later to become known as the Scarecrow) Fear Aversion therapy program. Croc grew up in Arkham Asylum and was released when Ras' al Ghul's ninjas freed him along with his inmates and the Scarecrow himself. Croc was one of the inmates to escape the incident in the Narrows and joined a group of inmates that fled underground with the Scarecrow. There, Scarecrow continued to experiment on Croc by injecting his Fear Toxin into parts of his body.