The Poor Kid/Trivia

Trivia

 * Matt Stone and Trey Parker officially confirmed the name of Kenny's sister to be "Karen", after years of fans referring to her by that name.
 * Kevin and Karen McCormick have undergone a slight redesign for this episode.
 * This episode showcases Butters' computer knowledge.
 * Kevin's voice has changed since his last speaking appearance; he sounds much more like an alcoholic.
 * Kenny is referred to as "Kenneth" by Mr. Weatherhead, which is his real first name.
 * It is revealed that Cartman is the second poorest kid at South Park Elementary (or at least in the 4th grade).
 * Kenny, as Mysterion, shows his fighting ability, and was able to take out a larger girl with extreme ease, as well as kicking her in the head whilst jumping.
 * It is revealed that Liane Cartman works two jobs, however it isn't revealed what those jobs are.
 * We also learn she no longer uses drugs, despite being referred to as a "crack whore" in "Pinkeye" and her own mother referring to Eric as the only person in the family who wouldn't use her money to buy cocaine in "Cartmanland"
 * This is the first time Kevin McCormick has spoken since the Season Two episode, "Chickenpox", made 13 years prior.
 * We hear Mysterion's signature music from the introduction of "Mysterion Rises" again during his fight with Jessica Pinkerton.
 * Stan's voice has gone back to a higher pitch.
 * Cartman makes a total of ten "Yo Mama" jokes in this episode.
 * Kevin is oddly not seen with the Weatherheads' other foster children cleaning the house or eating dinner, and is essentially after the McCormick childrens' introduction to the home. He is, however, seen in The Punishment Room scene.

Continuity

 * This is Karen McCormick's second appearance, her first being in "Best Friends Forever" as well as her first speaking role.
 * This is Kevin McCormick's first appearance since the episode "Sexual Healing".
 * Kenny reprises his alter ego, Mysterion, in this episode - however, unlike previous appearances, the episode focuses on both "Kenny" and "Mysterion", rather than just one or the other. This is also the first time Mysterion appears alone without Cartman as The Coon.
 * This episode marks Kenny's first death and appearance as Mysterion since last season's episode "Coon vs. Coon and Friends". This is also his only death in Season Fifteen.
 * This marks the first time people have acknowledged Cartman's peculiar way of pronouncing certain words and names, such as pronouncing "Kyle" as "Kyahl", "Kenny" as "Keeny", and saying "meem" instead of "mom".
 * This is the fifth time Cartman has been in jail; he was previously jailed in "Cartman's Silly Hate Crime 2000", for fighting with Token Black; "Die Hippie, Die", for kidnapping hippies; "Casa Bonita", for kidnapping Butters Stotch (implied but not shown on screen) and "Whale Whores", for destroying a Japanese whaling boat.
 * This is the second time Cartman has had his mom arrested; he has previously done so in "The Wacky Molestation Adventure".
 * This is the third time Kenny's parents have been seen arrested. The first time was in the episode "The Wacky Molestation Adventure", when they were falsely arrested under the belief that they were molesting their kids, and the second time was in the "Mysterion Rises", when it was revealed that they were arrested at a Cthulhu Cult Meeting ten years ago.
 * Kevin McCormick speaks with a slow slur and can be seen on the short school bus in earlier episodes, indicating that he is either mentally disabled or regularly intoxicated.
 * The meth lab at the McCormick residence was mentioned in "Lil' Crime Stoppers", when the mob boss mentions that they will have to have the McCormick's start making their meth again.
 * Greeley was last seen in "The Losing Edge", where the boys played baseball against the Greeley team and won.

References to Popular Culture

 * Mysterion paraphrases Yoda's famous quote, "Do or do not, there is no try" from the movie The Empire Strikes Back, telling his sister, "Don't try Karen, do.".
 * The foster family is an exaggerated caricature of agnosticism, mocking the ambivalence of agnostic beliefs. It is also a parody of the narrative cliché of highly religious, abusive foster parents.
 * The Weatherheads bear similarities to many stereotypically strict foster parents, such as the Dursleys from the Harry Potter series, Aunt Sponge and Aunt Spiker from the book and movie James and the Giant Peach, and the Wormwoods from the book and movie Matilda.
 * The name of the Weatherhead foster family may be based on Leslie Weatherhead (1893-1976), who is considered to be the founder of the school of agnostic thought.
 * Jokes were repeatedly made in reference to the Penn State scandal. Cartman also points out that these jokes are retellings of ones made in reference to the Catholic Church's sexual abuse scandals.
 * This is the first episode to refer to Dr. Pepper by name.
 * A man witnessing the McCormick's arrest is wearing a Diablo II shirt.
 * Mr. Adams closely resembles the character Zach Galifianakis played in the movie Due Date. His character Ethan Tremblay/Chase regularly thought of himself as a comedian and gave his audience signed photographs of himself.
 * White Trash In Trouble is a parody of the real-life reality TV shows such as America's Most Wanted and COPS.

Goofs

 * When Jessica is kicked to the ground, she doesn't have a black eye. But when Mysterion pulls her head up, it appears. This was due to the black eye not being included in one eye animation - when Jessica is initially kicked, there is a black eye visible.
 * When Mr. Weatherhead first takes a sip of Blue Ribbon, the question mark symbol disappears.

Kenny's Death

 * Kenny is unexpectedly killed by a "giant reptilian bird" moments before the end of the episode. His death is a callback to the "Agnostic Code" that his foster parents teach their adoptive children, specifically the part that reads "Then again, there could be a giant reptilian bird in charge of everything".
 * The "Oh My God, they Killed Kenny!" and "You bastards!" lines are not used, instead Stan simply exclaims, "What the fuck?".