The Batman Villain Project - #5 - Copperhead
First appearance - Brave and the Bold #78, (June 1968)
"The criminal known as Copperhead first appeared in Gotham City in a snake costume. He committed numerous thefts before finally being apprehended by Batman and the first Batgirl. Copperhead then turned to more deadly pursuits as a super-assassin, constricting victims to a suffocating death with his costume's tail."