Killer Croc (Waylon Jones) is a supervillain appearing in American comic books published by DC Comics. Created by Gerry Conway, Don Newton and Gene Colan, the character was introduced in Detective Comics #523 (February 1983). He has become one of the most enduring enemies of the superhero Batman and belongs to the collective of adversaries that make up his rogues gallery.

In his comic book appearances, Killer Croc is depicted as a former sideshow wrestler who suffers from a rare genetic condition that gives him a reptilian appearance and superhuman strength. Driven insane by this, he turned to a life of crime, over time developing animalistic tendencies. The character has also been a member of the Suicide Squad, debuting in the fifth volume of the comic series revolving around the team, and a romantic interest of Enchantress. While typically portrayed as a supervillain, he has also been occasionally depicted as an antihero.

The character has been adapted into various media, most revolving around Batman. Killer Croc made his live-action debut in the 2016 DC Extended Universe film Suicide Squad, portrayed by Adewale Akinnuoye-Agbaje. A version of the character appeared in the third season of the Arrowverse series Batwoman, performed by Heidi Ben.

Killer Croc was created by writer Gerry Conway and artist Gene Colan. The character made cameo appearances in Detective Comics #523 (February 1983) and Batman #357 (March 1983), with his full first appearance in Detective Comics #524 (March 1983).

Waylon Jones was born with a rare form of atavism that imparted him with reptilian traits with his birth causing the death of his mother. He was raised by his aunt, an abusive alcoholic who called him names like "lizardboy" and "reptilian freak". Croc eventually killed his aunt and became a criminal in Gotham City. After committing several murders, he faced off against Batman and the new Robin, Jason Todd, who defeated him.

In these original, Pre-Crisis appearances, Killer Croc resembled a powerfully built man covered entirely in green scales, but was still basically human in his facial proportions and build. He was also originally depicted as killing Jason Todd's parents. (This was later retconned to make Two-Face their murderer.)

Killer Croc escaped custody and sought revenge on Harvey Bullock and two other criminals who got him in jail. Batman tracked him down and Croc went into a homicidal rage. When new water tunnels were built, which would flood Killer Croc's new home, Croc seemingly sacrificed himself to hold the water back when they finally were open.

In reality, Croc was buried under rubble and was freed from his prison by storm drains. Killer Croc survived on rats and was isolated for months, driving him further into madness. Croc later went on a rampage after a confrontation with a vagrant, and winds up in a shopping mall. After delivering several blows to Croc, Batman (Jean Paul Valley is posing as Batman) is distracted by a glimpse of Bane. Croc then grabs Batman and tries to break his back. He fails, and Bane pits himself against Croc, breaking his arms. Croc is then put back into Arkham Asylum.