In "Sweet Stench of Sucess", the resturaunt Bloo "Deo" is at is called "Nice Burger", a parody of Good Burger from All That.

This is also kinda interesting. There was a 2003 Powerpuff Girls picture book called "Powerpuff Girls save Halloween", and while the kindergarten class are telling scary stories, an imaginative little girl comes up. This is what she looks like:

1. Chin-length brown hair
2. Red tee
3. Black sneakers
4. Sonewhat-squarish head shape

Hmm.....

This isn't really a secret, but it's a sighting.

In Cheese A Go-Go, Frankie's trying to find Bloo in the cinema.

As she walks along the annoyed viewers of the movie, one of them is Frankie's dumped boyfriend, Dylan.

So it appears that Frankie's dumped boyfriend has a very brief cameo in the episode.

I don't see how Herriman looks anything like Mayor from PPG.

His facial features are nothing like Mayor. His accessories can't be taken into account.