"Want to break up a monopoly? Analyze its functions and improve on them."
At eleven chapters (plus four interludes) and a running time of over a year, "The Popsicle War" is the longest and most ambitious Penny and Aggie
storyline. It resolves several of the comic's longest-running plot threads involving the title characters, Karen and Marshall, while advancing other supporting characters' storylines.
The opening chapter begins in July of the summer between sophomore and junior year for most of the cast. (Meg and Marshall are about to enter senior year at their respective schools.) Penny, grounded for the summer and spending time at home with her friends, welcomes a new member into her inner circle: the upbeat, seemingly ditzy and celebrity-obsessed Cyndi Kristoffer. Brandi is somewhat guarded towards her, hoping that she "works out better" than Katy-Ann, whom Penny had recently expelled from the group.
There follows a flashback to October of freshman year, in which a noticeably plainer-looking and shyer Penny falteringly attempts to ask out the handsome jock Braz Tyler, only for Meg to beat her to it, humiliating her for good measure. Meg later offers Penny a faux-apology and invites her, Sara and Michelle to a slumber party. Penny accepts, explaining to Sara that Meg's simply trying to keep her enemies close, while she and Michelle have a plan of their own: taking candid, unflattering photos of Meg at the sleepover. When they circulate pictures of her cavorting in ragged, mismatched sleepwear, Meg's reputation as "queen bee" is ruined, paving the way for Penny to take her place.
Flashing forward to the August after sophomore year, the main story resumes with Karen gathering a clique, consisting of Meg, Samantha, Charlotte...and Cyndi, a double agent. Although it's clear from their first meeting at the mall food court that they dislike each other and don't get along, Karen has chosen them not only for their shared hatred of Penny, but also because, in her analysis, each one corresponds in function to a member of Penny's clique. As Samantha and Charlotte offer laughably heavy-handed and unrealistic suggestions for attacking Penny, Karen suggests a subtler strategy: going after her subordinates and indirectly tapping the resources of Penny's other, more successful nemesis, Aggie, while at the same time ensuring she and her friends don't beat Karen's clique to the top. For this purpose, she's enlisted the help of Helen, who's already part of Aggie's group.
Meg points out that they can't become the most popular clique simply by defeating Penny's; they must provide an alternative social scene. Karen says she and her "other major ally" are working on that. The scene shifts to Karen meeting at home with Stan who, still bitter over Rich's injury and departure, has his own reasons to get revenge on Penny. Noticing Karen casually flirting with him, and still looking for a way out of his relationship with Michelle, Stan tries to get Karen to cheat on Marshall with him, and when she resists, suggests outright that she dump him, as she'd then be even more desirable and popular. Faced with Karen's adamant refusal to do either, Stan gets down to brainstorming ideas for parties that would be more enticing than Penny's. "How well do you do with frozen drink mixes?", he asks her, giving the arc its name.
- Alpha Bitch: Meg, in her backstory.
- Call Back: Freshman Penny's bringdown of Meg in this chapter expands on an allusion to the same event in the comic's first storyline. More significantly, the Flashback shows that Meg was far from an innocent victim.
- Completely Missing the Point: Meg says of Sara, "We still need to find out why she's dressing so dyke."
- The Dog Bites Back: Penny to Meg in the flashback.
- Even Evil Has Standards: Karen refuses to cheat on Marshall, or even to break up with him so she can sleep around, not even to defeat Penny.
- Five-Bad Band: Karen's clique, assembled so as to parallel Penny's Five-Man Band:
- The Big Bad: Karen, corresponding to Penny (The Leader)
- The Dragon: Meg, corresponding to Sara (The Lancer)
- The Evil Genius: Cyndi, an ironic counterpart, in more ways than one, to Michelle (The Ditz, instead of The Smart Guy). In fact, Karen doesn't see Cyndi as a genius, but rather as "visual relief and a good follower," like Michelle. However, as "The Popsicle War" progresses, Cyndi will show herself to be not such a Ditz after all.
- The Brute: Samantha, corresponding to Brandi (The Big Guy).
- The Dark Chick: Charlotte, corresponding to Katy-Ann (The Chick)
- Everything Is Racist: Samantha's attitude towards her "whiiiiite" allies, particularly Meg.
- Flashback: To Penny's freshman year and the beginning of her rivalry with Meg.
- Handsome Lech: Stan.
- Keeping the Enemy Close: Discussed and defied by Penny with regard to Meg, in the Flashback.
- The Mole: Cyndi in Penny's clique, and Helen in Aggie's.
- Pride Before a Fall: Meg, in her backstory. Also discussed amongst Meg, Samantha and Charlotte, the latter of whom, in a snarky aside to Cyndi, points out that this formulation of the saying is in fact a misquote of Proverbs 16: 18: "Pride goes before destruction, and a haughty spirit before a fall."
- The title of the arc as a whole is an allusion to Robert Cormier's young adult novel The Chocolate War, which in its own way also deals with the debilitating and dangerous effects of high school cliques, as well as with attempts to challenge that social order.
- The chapter title alludes to the DC Universe's Injustice League, Evil Counterpart to the Justice League of America.
- The Social Expert: Karen assembles a clique modelled after Penny's, with a view to each member's strengths as she perceives them and as they bear on her war against Penny.
- You Watch Too Much X: After Samantha suggests hiring another biker to seduce Penny and then humiliate her on camera, Meg points out her obvious lifting from John Tucker Must Die. When Samantha later asks how the clique can make use of Aggie, Meg says, "Maybe we could rip off a movie plot."