Batman turns to controversial methods to help combat Superman's regime. He's spliced Joker's toxin and Ny's pheromones' to help "recruit" members of the regime to his side. With the help of the Question and Red Hood, he uses the mixture on Wonder Woman, Raven and Hawkgirl to create new "Harleys".
"I never thought Kal would be so easy to catch off guard!"
Indeed! Specially when you're decked in Kryptonite and wearing the iconography of his enemies. There probably was an easier way to deal with him if he was so pants-on-head retarded.