Waylon Jones was born with an extreme form of the medical condition "Epidermolytic Hyperkeratosis", which caused his appearance to develop progressively into that of a crocodile, hence his name. As a teenager, Waylon had no friends, and was the object of ridicule of those who knew him. He found a job in a carnival sideshow ... wrestling alligators. It was at this point that Waylon began referring to himself as Killer Croc. Even then, his strength level was greatly beyond that of a normal human. Croc realized that there was more money to be made in crime, so he set out to become Gotham's most powerful underground figure.
When the Justice League arrive in Gotham to remove the patients at Arkham Asylum, only to meet resistance from Batman, Killer Croc observes the argument between the heroes in silence until Cyborg angrily attacks Batman after discovering the virus he had uploaded into him during their first meeting, with Croc commenting that as "Pretty evil." When Harley Quinn releases all the inmates to attack the heroes, Croc goes straight for Batman, preventing the Dark Knight from coming to his son Robin's aid as he's dragged underground by Solomon Grundy.
Injustice: Gods Among Us
Killer Croc appears in the Arkham Asylum stage. He is in the recreation area with three other Gotham villains, and beats the player/opponent up if they're thrown into the room.
He also appears in one of Batman's S.T.A.R. Labs Missions where he frees inmates at Stryker's Island and Batman must defeat both the inmates and Killer Croc, while dodging Croc's Shoulder Charge attacks.
Injustice: Gods Amoung Us Mobile
Killer Croc is a playable character in Injustice: Gods Among Us' Mobile Game.
Injustice 2 Comic
Killer Croc was seen as one of the members of the Suicide Squad. Though the squad is originally assembled by Amanda Waller, she is ambushed and killed by Batman, who takes control of the squad himself. While Croc attempts to attack Batman, he is knocked out and carried away by Orca. After this, the tablet containing the triggers for the Suicide Squad's bombs is given over to Ra's Al Ghul, and Croc loyally, albeit forcefully, follows Al Ghul's orders. He and Orca later kill Ra's hostages, including Ted Kord as his first move against the Batman and the United Nations. Croc later joins the other members of the squad in trying to defend their base from Batman's raiding party, but he is knocked out by Harley's party. When Grodd rebels against Solovar's leadership, Croc helps defend Ra's from the Grodd's faction, even eating the head of one gorilla to help Orca. Later, during a feast in Gorilla City, Killer Croc learns of Orca's pregnancy and proceeds to walk out of the room. Deadshot begins asking Croc a wide variety of questions regarding his relationship with Orca, who silences the sniper by crushing him on a wall. Despite this, he is visited by the other members of the squad who encourage him to propose and marry Orca. Eventually, Croc follows their advice and proposes to Orca, which she accepts. In the following day, the two are wed, but as they exit, they are met by Ra's. Al Ghul promises to give the two a happy ending, and deactivates their bombs, but Croc and Orca lash out at Ra's for controlling them through the bombs. In revenge, Croc bites off one of Al Ghul's arms and swears to eat him. The action is interrupted by a returning Grodd, who picks up the trigger for the Suicide Squad's bombs. Grodd states that he will detonate the bombs of the other members, and Croc attempts to attack the rebel. Orca, however, convinces Grodd to keep the squad alive and use them for his own purposes, which he agrees to. Content that his friends will live another day, Croc departs with Orca.
Killer Croc now lives in the sewers running through the Batcave in Injustice 2, for some reason. He assists the player character during the stage transition by smashing the opponent numerous times into a wall before the wall breaks.
Powers and AbilitiesCroc is about as strong as his physique would suggest, even if his strength is nowhere near the levels of other metahumans like Superman. He also has teeth, strong enough to bite through steel and human flesh. Croc also possesses an immense healing factor, able to heal himself faster than a normal human's healing. His skin has also hardened to the point where he is practically immune to abrasion or even bullets. Though not as proficient as Batman, he is a capable fighter, skilled in wrestling and street fighting. His speed and agility is also impressive. True to his name, he is also an adept swimmer, able to hold his breath for some period of time.
Killer Croc is a massive human mutated into a reptile like appearance, complete with dark green scales all over his body with a light green color on his stomach and long claws jutting from his fingers, with only a pair of orange prison pants and chains attached to his wrists serving as a form of clothing.