Harley announced: 'Do you want to see a show?' and they started to chant 'Kill,' as Mister Hammer tried to beat Dr. Baker pleaded that she couldn't do anything, but Harley called her a quack, and then kicked her from Joker's office onto the floor below. When Batman went to Joker's Funland and tried to find Joker, who remotely tried to assassinate Catwoman, he went into the vents and tried to surprise Joker, but he came into the middle of Harley's announcement. Ever since, the Abramovici's operated alone in Gotham City, and later Arkham City, however, Sickle always had a disliking for Joker for separating him from his brother.

Hammer to be his 'right-hand man' and left Sickle for the Penguin, who hired the twin to be apart of his gang. After the surgery was completed, Joker favorably chose Mr. Thomas Elliot to perform the surgery and who cut the twins in two.

During a fight between the Abramovici's and Batman, Joker had an ingenious idea to separate the brothers, and acquired the help of Dr. However, he subsequently turned up with a Glasglow smile that was carved into his face, and the twins were recruited into Joker's gang. Joker sent his cohort, Harley Quinn, to recruit the twins, but the circus manager refused. Mister Hammer and his brother, Sickle, were conjoined and orphaned twins who performed in a Russian circus, and who developed a reputation for brutality which attracted the attention of the Joker.