Although one is allowed, at least at my home, to slip into childhood now and again, especially at a comic book convention, there are some people who don’t need a vacation from adulthood because they failed to move forward out of high school and teenage dreams. You might know some of these people who still want to party like they did in high school away from their parents or in college, often on their parents’ dime, even as they leave their twenties and enter the workforce.

The movie “Young Adult” is about one such monster in the form of the former prom queen Mavis Gary, played with a fearless abandon by Charlize Theron. Gary has had moderate success as the ghostwriter for a young adult book series at a time when most young adults don’t read books. She left the small town of Mercury for the Mini Apple (Minneapolis), got married and divorced. She wakes up in a stupor next to some guy she picked up the night before but what shakes her out of her boozy bed-hopping routine is an email with a baby announcement. Her ex-boyfriend and his wife have just had a baby. That baby, Mavis believes, should have been hers, and she and her ex (Patrick Wilson) are meant to be, but another old school mate, Matt (Patton Oswalt) clearly sees that Mavis has gone mental.

Matt didn’t even register with the golden girl prom queen that Mavis was although their lockers were next to each other. To Mavis Matt was “the hate crime guy,” the victim of a vicious attack by a goon squad of football players who mistakenly believed he was gay. That left Matt with a gimpy leg and slight sexual dysfunction. He’s also a home brewer of artisanal booze that Mavis happily guzzles instead of respectfully sipping.

Director Jason Reitman bravely doesn’t allow Theron to give Mavis any redeeming qualities. She’s beautiful, but only looks her best at night. She might have been envied during high school when selfishly scheming to get a guy was considered the pastime of the popular crowd, but in small town hicksville of married couples, she’s an object of pity. The movie would have been unbearable without the character of Matt and Patton Oswalt as the overweight outcast ranges from snarky funny to guarded and finally to tenderly tentative in his exchanges with Mavis.

In the Q&A that followed, Oswalt riffed on action figures and Star Wars as well as owning a French bulldog. His Grumpus, a fawn-colored dog with a black mask is the cutest dog but suffers from the worst design. “All it does is fart and die slowly.” French bulldogs “adorably die slowly.”

Oswalt also confessed to beginning his preparation for the role of Matt 20 years before the script by taking that time to build an upper body physique that is a “living tribute to Walter Matthau.”  Yet on a more serious note, he cautioned against attending your high school reunions to gloat. Some of your cliches will get busted and some will get reinforced. That former prom queen may still be beautiful and end up a brain surgeon or not.