Why does the series start off as a light-hearted superhero adventure and gradually delve into deeper topics and gain complex characters? Remember that the series is written byGeorge and Harold. As they go through school, their teachers introduce them to the literary greats. George and Harold take inspiration from these works, which is also why the books have a title based on one specific novel.
After defeating the Mayor, Dog Man ends up taking her to "Mayor Jail". At first glance, this might seem like a cute gag...until you wonder why they need a jail specifically for mayors. How many Corrupt Bureaucrats has this city had?
Fridge Brilliance: Unless you remember the gag from Terrifying Tale of the Tattle-Tron 2000 where Melvin (as mayor) arrested so many people that they had to build, in addition to men's and women's prison and Juvie, a "baby jail," a "dog jail," a "frog jail," and many more, with Melvin himself ultimately ending up in the "Jail for dumb nerds" in that book. Then in the next comic (War of the Wily Wonder Nerd) where he's also the villain, he ends up in the "Jail for dumb stupid nerds." In other words, all those extra, empty, oddly-specific jails may be a permanent characteristic of George and Harold's comic universe.
The intro chapter of For Whom the Ball Rolls reveals that Harold helped co-write this story. Then you see Petey’s character arc of this story, which specifically is about his father, who abandoned him when he was young, coming back into his life and treating him horribly. This is definitely a Fridge Tearjerker when you know Harold’s backstory as revealed in the 9th Captain Underpants book, but this quickly turns to Fridge Horror when you reach the scene of Petey’s dad “accidentally” smashing dinner plates all over the place as Petey and Lil’ Petey cower in fear. Did Harold just subtly imply that his father was physically abusive?
If you really think about Dog Man's origin story, it is really dark. The cop's head would have contained his personality, so when it died, the cop effectively died. Imagine you and a loved one are both mortally wounded, your loved one cannot be saved, and the only way to save you is to chop off both of you heads and stitch your head on your loved one's body. Now imagine every time you look at yourself in the mirror, you see the corpse of someone you cared about...
