Big things are happening on TV Tropes! New admins, new designs, fewer ads, mobile versions, beta testing opportunities, thematic discovery engine, fun trope tools and toys, and much more - Learn how to help here and discuss here.
Laser-Guided Karma: Peter and the popular kids suffer this after tormenting Meg. And Lois all but getting the same treatment after refusing to hear her out earlier regarding the story she gave about the inmate and forbidding her from seeing him again, which led to Lois' current predicament in the first place.
Pet the Dog: Brian telling Meg that she is "far sweeter and kinder than the typical American girl."
Prison Rape: Presumably what happened to Meg in prison, and hence her current demeanor.
Rape as Comedy: It is implied that a bull — a 1,000 male steer — rapes Peter. Never mind the sheer ridiculousness of this (humans romancing animals they think are people have dated to the beginnings of Western Animation), but if a steer were actually able to sexually assault a human being, the man would surely be killed, if not severely sickened and violently injured.
Peter suffers more of this later in the episode, when Meg returns home from prison and repeatedly assaults him sexually.
Recursive Canon: Peter finds out the plot of the episode by reading it from TV Guide.
Temporarily a Villain: Meg. Justified in-story as she went to prison and had to fight for survival, and justified in the fandom as revenge to all the people who have treated her like crap throughout the series.
Too Dumb to Live and What an Idiot: Brian. While he tries to talk Meg out or robbing Mort's pharmacy, it doesn't occur to him that trying to reason with her with words would get him killed.
Connie. Did she not notice or care that Meg's time in prison would make her violent? Apparently not, because she still makes fun of her before having her ass handed to her.
Woobie, Destroyer of Worlds: Meg at the end of the episode holds Mort's pharmacy hostage and is one police call from falling even deeper right before Brian defuses the situation by reading her the article he wrote about her.