Born with a rare mutation that made his skin green and scaly and grew his body to grotesque proportions, Waylon Jones was raised by an abusive aunt and bullied relentlessly for his appearance. He briefly worked as a carnival freak under the name Killer Croc, but his misanthropy grew as did his bestial nature, pushing him to a life of crime. As his physical condition and mental state deteriorate, Killer Croc becomes a more bestial foe, increasingly detached from humanity.