Joker has captured Batgirl (but like, in a totally original way); he plans to break her down and test his new laughing serum on her! He makes her degrade herself verbally, strip out of her suit, and finally suck him off while she has the occasional fits of uncontrollable laughter! There's something else in his new formula that makes Batgirl insanely horny, and before long she's begging for Joker to fuck her, needing no prompting from him anymore to confess what a filthy useless whore she is for Batman.