Well, Barbara. So you finally admit it, you finally admit to being Batgirl. I didn't see it at first, it's why I made all those sexual advances on you and kept commenting on your slutty outfit, sorry about that, but the fact that Batgirl retired as soon as my daughter was put in a wheelchair and then came back right after she was healed made me suspicious. Not suspicious enough to make me stop making sexual advances that were inappropriate in retrospect, but suspicious nonetheless.
And to answer your question. No, it's not mine, after he was put in my custody, I did an inspection of the Joker's rectum to make sure he didn't have any tricks up his ass for when he gets raped in order to finally end his menace. Good thing I checked, you would not believe how many exploding dildos and acid beads that freak had stuck in there. But even then, I'm sure he has more stuff hidden in there that I just couldn't see. That's why I can't be the one to rape him, YOU have to be the one to do it Batman, only your superior detective skills could overcome the Joker's anal traps and rape him once and for all. Do it Batman, for Gotham.