pun - ouch
Another one of those cartoon references that's not meant for the kids....
So the police detective comes home and finds a pizza-delivery flyer under her door. From "Lee N' Cavalo's Pizza". Heard, rather than read, and the mind is off to the opera....
[addendum - after seeing the rest of the cartoon] The villain was The Joker, and his next crime (after kidnapping the police detective) was trying to steal an historic costume of Pagliacci, the sad clown, from the Gotham City Opera (which looked remarkably like Sydney, but without the harbor).