The madman known as the Joker is an original and cannot be duplicated. Well, actually, he can be and has... at least on Earth-One and Two, where there are two Harlequins of Hate plaguing each Gotham City. And, just like them, other parallel planes have equally appauling emotional enemies of everyone. On Earth-S, instead of a laughing maniac there is a sobbing sycophant... the Weeper!
Actually there were two Weepers who appeared on the scene. The first was Mortimer Gloom, a former circus performer turned master criminal using various devices including tear gas on his victims. Facing Bulletman and Bulletgirl on a few occasions, including as a member of the Revenge Syndicate, he ultimately met his end through undisclosed means. Nevertheless, his son Mortimer Jr. took over for him, seeking retribution by trapping Bulletgirl, although the heroine was able to defeat him with the aid of Mary Marvel.
On Earth-One, there was a Willie the Weeper who on one occasion assisted the Joker there as had Earth-Two's Joker when he journeyed to Earth-S to meet the son of the original. Each time, the pairing was short lived and led to defeat of the pair, showing that opposite temperments didn't mix well in their aspirations of villany.