Former Child Star Sarah Lynn, who once played Sabrina on Bojack's sitcom Horsin' Around, has just turned 30. When she happens to encounter Bojack at a furniture store, she quickly reveals just how messed-up her life has become. Her boyfriend, Andrew Garfield, breaks up with her, and in response she downs a bunch of pills, stabs herself in the stomach, and takes a dump on a couch.
With nowhere else to turn, Sarah Lynn drops by Bojack's place and asks if she can chill there for a little bit. Bojack, thinking that it'll be a great way to recapture the glory of his Horsin' Around days, lets her stay. She repays the favour by doing lots of drugs, holding wild house parties, and destroying the furniture and many of Bojack's belongings.
Diane and Todd try to convince Bojack that Sarah Lynn is nothing but trouble, but Bojack doesn't want to ruin the fantasy of acting as her father figure again. He's also dealing with his weird sexual attraction to her, which turns out to be mutual once they sleep together, further compelling him to keep her there.
"Prickly Muffin" contains examples of:
- All According to Plan: Princess Carolyn tries to poach Sarah Lynn as a client by acting as a spoiled Man Child, dressing accordingly, attending Sarah Lynn's parties in Bojack's house and interacting with her to subtly push her into thinking they both think alike and should work as a team. When Sarah Lynn chooses Princess Carolyn's rival, Vanessa Gecko, instead, the former seems to be broken by that revelation and the wasted effort until Sarah Lynn leaves, at which point she changes stories and instead talks to Laura about "everything going according to plan" and to set a meeting with Andrew Garfield, Sarah Lynn's ex-boyfriend and the true target. Whether she's being honest or just decided to wing it is open to interpretation.
- Attention Whore: Hoo boy, Sarah Lynn.
- Black Comedy Rape: Not "rape" per se, but Todd is clearly not happy to be dragged into Bojack and Sarah Lynn's love-making.
- Bloody Hilarious: Sarah Lynn does it when she finds out her boyfriend Andrew Garfield is leaving her. What does she do? Stab herself with some rusty bayonets in order to draw attention from the public to their breakup, precisely what Andrew wanted to avoid, resulting in a spray of High-Pressure Blood.
- Cast Incest: In-universe—Bojack and Sarah Lynn, who played a father and his adopted daughter on Horsin' Around, end up sleeping together.
- Catchphrase: In the episode of Horsin' Around at the beginning of this episode introduces Sabrina's catch-phrase: "That's too much, man!"
- At the end of the episode, Sarah Lynn also introduces us to her new catchphrase, which will be used liberally throughout the series: "Suck a dick, dumb shits!"
- Comically Missing the Point: When BoJack asks Diane what she thinks about Sarah Lynn, she doesn't pick up that he's referring to her living with him and instead offers an in-depth analysis on her thoughts of Sarah Lynn as a person and her career. To her credit, it's quite insightful and does the opposite of paint Sarah Lynn in the Puppet of the Industry light (directly saying that she feels a lot of people dismiss her as that). Still... not the point.
- Sarah Lynn's "Prickly Muffin" music video is shot almost entirely at a planetarium. Sarah Lynn would reveal the Planetarium to be her favorite place in "That's Too Much Man".
- This is the first instant that it's revealed she wanted to be an architect via flashback. She reinforces this a few times during "That's Too Much, Man!" and her final words are "I wanna be an architect."
- Her quote about surrounding her with sycophants and enablers until she dies tragically young is Played for Laughs, but is Harsher in Hindsight when she dies via overdoes in "That's Too Much, Man!"
- The Friends Who Never Hang: Discussed. Todd tells Diane that they never hang out much. This is averted in later episodes.
- Hard-Drinking Party Girl: Sarah Lynn epitomizes this.
- Impact Silhouette: A lemur leaves one after Todd tells BoJack that they live in the real world.
- "The Reason You Suck" Speech: Sarah Lynn gives one to BoJack.Sara Lynn: "You sit up here in your little house and feel sorry for yourself? Ugh, guess what BoJay: in order to be a has-been, you actually have to have, y'know, been!"
- The Stoner: Sarah Lynn.
- This Is Reality: BoJack cites Horsin' Around as an example of good parenting; Todd responds that this is real life, not a TV show. He is immediately interrupted by a flaming lemur running into the room and smashing through the wall on the other side, leaving an Impact Silhouette in his wake.
- Title Drop: "Prickly Muffin" was the Horse's Affectionate Nickname for Sabrina on Horsin' Around. Sarah Lynn later uses it as an Unusual Euphemism in one of her songs.
- Sex Sells: What Sarah Lynn says is the message behind her music
- Unusual Euphemism: "Prickly Muffin" obviously refers to one's vagina, at least in Sarah Lynn's song; on Horsin' Around it was an Affectionate Nickname.