Killer Croc in Batman: The Animated Series.
Born in the slums within the everglades of Florida, Waylon Jones had a rare condition that gave him reptilian-like skin. Viewed as an outcast he became a thief and was placed in juvenile hall. In juvenile hall, Jones killed an inmate with his bare hands who made fun of his appearance and was sentenced to jail. Paroled after 18 years, he found work as an professional wrestler and took the name "Killer Croc". He stole the wresting promoters money, escaped to Gotham city and became a master thief, extortionist, and murderer.
Killer Croc in Batman: The Animated Series
Killer Croc in The New Batman Adventures.
Killer Croc with a coat and hat
Killer Croc in The New Batman Adventures.
Killer Croc Robot in Batman Beyond
Killer Croc, Two-Face, & Mr. Freeze dummy in Batman Beyond: Return of The Joker