It took me a bit, because I was reading the first pages with the guy Jonny as the narrator so I thought it was him thinking that while stumbling upon the scene of Joker crying. Oops, yeah. So re-read with Joker telling Harley all this, it makes a lot of sense. It's strange to think of the Joker as being bullied as a youth. The need to be in control to the situation. The need to be the one that threw the toad off the roof. The fact that he went looking for it afterward, shows he obviously cared a great deal for the creature. Haven't read the comic so I can only guess that it may have been his best and possibly only friend? Sad, but I get the whole "So I did it myself." The unspoken part of that is "So they wouldn't have the satisfaction [of doing that to me]." It's one of those rare glimpses, a blink and it's gone. I think Callisto from Xena said it best: "Sometimes it even scares me. Then I get over it."