the beginning of the sad demise of the caped vigilante (it looks like Robin doesn't want to be there, doesn't it?)

:D

Lmao!! Lol. :)

Yeah, but I was more concerned with cluttering up the space. And Batman is drunk anyway, I'm sure his singing skills are on a downward slope. :)

Isn't it 16 times?

I also thought it was 16. Then I listened to it carefully....something sounded odd. I went back, grouped the "na"s into pairs (it's easier to count them that way) and counted 7 pairs:
Nana, nana, nana, nana, nana, nana, nana....BATMAN!

I'm glad I have an unoccupied mind around to figure that out. ;) Seems like you'd be right. (Google is not terribly helpful.)