It's important to remember that in real life, Stephen Pastis (creator of Pearls Before Swine) and Jeff Keane (the current creator of Family Circus) are good friends. Characters from the Family Circus have shown up more than once in Pastis' strip, and -- according to the mythos of the strip -- there's a bitter rivalry between the two comics. Just keep in mind my first sentence.
This past Sunday Pastis not only managed to move the "war" forward, but also created a sequence that relies on the very nature of comic strips for its humor. (click on image to enlarge)
First, there's the disrupted sequence. Pastis provides clues as to how the strip should be reassembled (look at the surviving borders of the panels). Meta-humor indeed.
Second, note that a Family Circus panel is included (it's not the one run that Sunday, BTW. That would have been awesome). To the world, Bill Keane is still the creator of the strip, and sometimes hands off the Sunday strip to young Billy, who creates child-like cartoons and puns. Although Bill modeled the characters after his children, it was Jeffery, not Billy, who actually took over the creative duties after his father's passing.
So it's significant that Jeffery's the one who destroys Pearls Before Swine. Because that's the cartoon avatar of the real artist.
Humor working on multiple levels? That's what keeps me turning to comics page first every Sunday.