- Played by: Josh Thomas
The de facto head of the family. An entomologist from Australia, he becomes Matilda and Genevieve's legal guardian following the death of their father Darren. Since he's immature and self-absorbed, there's a bit of a learning curve.
- Big Brother Instinct: For all his self-absorption, he is does genuinely want to do right by his little sisters, and will usually take their side in any conflict. He even once dumped Alex because Genevieve felt uncomfortable around him.
- Camp Gay: Lampshaded by Nicholas in the second episode of Season 2. He knows he can be campy, especially around heterosexual people, but he does this on purpose because he feels they need it.
- Freudian Excuse: Many of his issues can be explained by his troubled relationship with his parents, where his dad left his mother for another woman, and then his mother spent years venting her feelings on him.
- Genius Ditz: Despite being inept at a lot of things, he is incredibly knowledgeable about bugs. Before being summoned to California, he was overseeing a conservation project in Australia.
- Hilariously Abusive Childhood: Nicholas claims that until he was twelve years old, his mother paid him not to leave her.
- Innocently Insensitive: Having spent years making friends with bugs, he doesn't always grasp how to deal with humans. In the first episode alone, he doesn't seem to grasp that Alex doesn't want to hear all about his dysfunctional family during their hookup.
- It's All About Me: He is really, really self-absorbed most of the time.
- Playing Up the Stereotype: He claims that he always acts gayer than usual around straight couples, because "they need it".
- Transparent Closet: He was in the closet until his twenties. Genevieve figured out that he was gay when she was seven and he was eighteen.
- Played by: Kayla Cromer
Nicholas' half-sister, and Genevieve's biological sister. A teenage autistic piano prodigy, she aspires to go on to the Juilliard School when she graduates high school.
- Alliterative Name: Matilda Moss.
- Big Sister Instinct: She wants to be a protective big sister, but is not always effective at this. For instance, when she and Genevieve were little and Genevieve got upset, she would throw a sympathy tantrum in order to get their dad's attention faster, but that would usually result in Darren dealing with her first. In the present, her ideas for helping Genevieve include arranging monthly condom deliveries.
- Brutal Honesty/Cannot Tell a Lie: She is almost always blunt and honest, to the point that trying to get her to lie risks causing her to suffer a meltdown.
- Endearingly Dorky: Played with — autistic Matilda's awkward-cheerful personality means that there are quite a few people who find her cute, like her crush Luke... which frustrates her, because she wants to be seen as "cool" and sexually attractive, which she's too awkward to pull off. A large part of her character arc in season one is learning to appreciate her siblings Nicholas and Genevieve, and her eventual girlfriend Drea, who all love her for who she is rather than the person she wishes she was.
- Ethical Slut: She has an arrangement with her girlfriend Drea; as Drea is asexual, while Matilda is not, Matilda is allowed to have sex with guys in order to fulfill her sexual needs, as long as these trysts don't become emotional or romantic.
- Gayngst: Inverted in season 2; Matilda's realization that she isn't homosexual (She appears to be best described as biromantic heterosexual as she's both romantically and sexually attracted to men but only romantically attracted to women) causes her some angst, because she fears that it will make her incompatible with Drea.
- Genius Ditz: She doesn't have a lot of real-world skills, but she is a brilliant pianist.
- Has a Type: By her own admission, she is attracted to black men.
- Hates Being Touched: She doesn't like giving or receiving hugs, and once her father dies, she asks that Nicholas and Genevieve not hug her anymore. This also temporarily halts her relationship with Drea, who uses hugging to manage her own hypersensitivity issues; fear of being intimate causes her to push Drea away, until Drea explains that she doesn't actually want a sexual relationship, just a romantic one.
- Hidden Depths: Besides her piano-playing skills, she is also surprisingly competent at treating injuries.
- Innocently Insensitive: Like many autistic people, she has difficulty reading social cues and can appear to be rude to other people. This is most notable in "Monarch Butterflies", when she nearly destroys her relationship with Drea when she initially refuses to go to the prom with Drea because she wants a "cool" date.
- It's All About Me: She has a lot of difficulty seeing things from other people's perspective.
- Motor Mouth: If no one stops her, she'll keep talking, and talking, and talking. Ironically, she used to be completely nonverbal.
- Queer Establishing Moment: There were hints that Matilda might not be completely straight in earlier episodes, but the ambiguity goes out the window in "Blue Death-Feigning Beetles", when Nicholas and Genevieve find her half-dressed and asleep with her arms around classmate Drea.
- Romance and Sexuality Separation: She loves her girlfriend Drea, but in season 2, realizes that she's not sexually attracted to her. Drea ends up being relieved by this, as she has since realized that while she loves Matilda, she's not interested in sex.
- Stepford Smiler: Beneath her cheerful exterior, she deeply misses her dad and feels constant pressure to act normal.
- Played by: Maeve Press
Nicholas' half-sister, and Matilda's biological sister, and the youngest child of the Moss family. Having grown up in the shadow of her older siblings, she is the most jaded member of the family.
- Brilliant, but Lazy: According to her teacher, she's a good student, but she doesn't put in the effort, preferring to hang out with Tellulah and Barb.
- Hidden Depths: "Discoid Cockroaches" reveals that she's a natural storyteller with some comedic talent. She's also an aspiring poet.
- Little Sister Instinct: She is incredibly protective of Matilda, to the point that she contemplates sabotaging Matilda's efforts to get into Juilliard out of fear of what would happen to her if she relocated to New York.
- Only Sane by Comparison: She struggles to deal with her father's recent death, coupled with suffering from severe teen angst, causing her to act out in bizarre and often incredibly stupid ways. Such as pretending to get high on her dad's heart medication, because she let friends Tellulah and Barb talk her into taking it, or the time she allowed Tellulah to enlist her in a scheme to solicit dick pics from a boy in exchange for a supposed picture of Tellulah's vulva (that was actually just a random picture they got off of the Internet). Nevertheless, she still comes across as the most level-headed and normal of the Moss siblings, compared to the immature, self-absorbed Nicholas (who once almost got dumped after thinking it would be a great idea to pour ceviche on his boyfriend's head) and autistic Matilda (who tried to arrange a threesome with two of her fellow autistic students, despite none of them knowing how to actually conduct a threesome.)
- The Resenter: She resents Nicholas because as long as he was around, their father constantly felt that he needed to give him attention, too, which meant that she herself got very little attention growing up.
- Straight Man: She is the closest thing to a "normal" person in the cast.
- Troubled Teen: Throughout the first season, her approach to coping with her father's death is to engage in stupid, risky behavior, like trying drugs or sexting, much of it at Tellulah's goading. After Tellulah goads her into picking a fight with a boy, resulting in her nearly getting suspended, she decides to try poetry instead. In season 2, Nicholas encourages her to express herself by making videos, which ends up boosting her confidence.
- Played by: Christopher May
The Moss family's late patriarch. A womanizer, he cheated on Nicholas' mom and produced Matilda, and later Genevieve. He dies of cancer in the first episode.
- Open-Minded Parent: He's surprisingly okay with Nicholas bringing Alex (at that point a random hookup) along for a discussion about his will.
- Parents as People: He tried very hard to be a good parent, but ended up failing all three of his kids in different ways. With Nicholas, he was absent and often hyper-critical. With Matilda, he tried too hard to force her to act "normal". And he ignored Genevieve or forced her to take on the role of co-parent for Matilda.
- Really Gets Around: After his second wife's death, Darren had a string of girlfriends.
- Played by: Vivienne Walshe
Nicholas' mother, and Darren's first wife. Still living in Australia, she calls her son up every now and then.
- Played by: Lillian Carrier
Matilda's classmate, and later her wife. Like Matilda, she is autistic, but is much more aware of her limitations.
- Boring, but Practical: While Matilda was preparing to go off to Juilliard to pursue her dreams of being a famous musician, Drea took courses in food preparation. She doesn't expect to do anything special with her life, but she won't starve, at least.
- Characterization Marches On: In the first season, she's not above sneaking a peek at Matilda while the latter is showering at school, and is quick to take Matilda up on her offer of no-strings-attached sex, but in season two, she is utterly mystified when Matilda tries to discuss sexual fantasies with her, which foreshadows her eventual realization that she's asexual. "Cave Cockroach" hangs a lampshade on the discrepancy; Drea's behavior in the first season wasn't driven by lust so much as a desire to be around Matilda as much as possible.
- Cuddlebug: She manages her hypersensitivity through hugging. Usually, the recipient is Duke, her support dog. Her insistence on embracing Matilda is one of the rough spots in their early relationship.
- Delicate and Sickly: In addition to her autism, she has a number of physical health issues, like Crohn's disease and colorblindness. Her mother has used this for years as a pretense to heavily control her life.
- Hidden Depths: She has a surprising array of interests, including entomology and Eastern philosophy.
- Loyal Animal Companion: She is never far away from her faithful support dog Duke.
- Nice Girl: She's not always great at social cues, but she is probably the most genuinely nice character in the whole cast.
- Romance and Sexuality Separation: She loves Matilda, but eventually realizes that she's homoromatic asexual. This suits Matilda just fine, as she loves Drea, but isn't sexually attracted to her.
- Previously Overlooked Paramour: Matilda initially ignores Drea's infatuation because Drea isn't "cool". After her own attempts to be cool blow up in her face, Matilda decides to give Drea a chance and finds that she likes her.
- Played by: Maria Bamford
Drea's mother, and Nicholas' new friend in season 2.
- Hair-Trigger Temper: She gets angry very easily, to the point that she has exercises to restore her calm.
- Mama Bear: She is extremely protective of her daughter.
- Played by: Richard Kind
Drea's dad, a real-estate guy.
- Played by: Ivy Wolk
Genevieve's best friend, and kind of a jerk.
- Attention Whore: Much of her bad behavior is an attempt to get other people to notice her.
- Bullying the Disabled: She's not above picking on Matilda, despite knowing full well that the latter is autistic. One episode sees her planning a party for Matilda as she waits to find out if she got into Juilliard... because she fully expects that Matilda will be rejected and suffer a meltdown in front of everyone.
- Put on a Bus: She does not appear in season 2. In the next-to-last Season 1 episode, Nicolas asks where she is and Barb simply mentions she has a boyfriend now (likely the boy she was confronting the episode before).
- Small Name, Big Ego: She likes to pretend that she's a Queen Bee Alpha Bitch, but the reality is that Genevieve and Barb are probably her only friends.
- Stupid Evil: She doesn't seem to care if any of her schemes end up blowing up in her face, as they frequently do.
- Toxic Friend Influence: She is a terrible influence on Genevieve and Barb.
- Played by: Lori Mae Hernandez
Genevieve's other best friend.
- Insane Troll Logic: In "Cave Cockroaches", she stops eating Tomato-based foods because she read on the Internet that they cause vaginal odors.
- Only Sane Man: She's usually the one who spots problems in Tellulah's plans.
- Played by: Christian Valderrama
Genevieve's classmate, and later her boyfriend.
- Dogged Nice Guy: He's trying his best to win over Genevieve, but, having little experience with boys, she doesn't always make it easy for him.
- Played by: Carsen Warner
Matilda's classmate. He has a crush on Matilda, but has been repeatedly rejected by her.
- Dogged Nice Guy: He's very good-natured, but Matilda just isn't interested in him.
- Put on a Bus: In "Gray Bird Grasshopper", Matilda mentions that Jeremy graduated and, having been unable to get into college, is now working at a factory.
- The Bus Came Back: Returns in the Season 2 finale to officiate Matilda and Drea's wedding.
- Stalker with a Crush: He has a very poorly-concealed crush on Matilda, and has repeatedly tried to ask her out.
- Played by: Mason Gooding
A hunky jock on the football team. Matilda has a crush on him early in the first season.
- Nice Guy: He is supremely patient with Matilda, even though it's obvious that she has No Social Skills.
- Put on a Bus: In season 2, it's mentioned that he's gone off to college.
- Played by: Charlie Evans
Genevieve's classmate, and later Tellulah's boyfriend.
- Jerk Jock: One of his first scenes sees him leading others in pelting Genevieve with tampons after finding out that she's on her period (although he later feels bad about it and apologizes.) In "Maggots", he tries to con Tellulah into sending him a picture of her vagina. When she sends a picture of someone else's vagina, he immediately shares it around school.
- Played by: Adam Faison
Nicholas' long-suffering boyfriend. Though he's handsome and in training to be a dentist, he has a desperate need to be liked, which causes him to be drawn into the Moss family and their insanity.
- Bigger Is Better in Bed: He self-deprecatingly jokes that the only reason Nicholas puts up with him is because he's well-hung.
- Characterization Marches On: In the pilot episode, Alex is a little irked and disturbed by Nicholas' past issues with his parents. This is very at odds with later episodes where, one of Alex's issues with Nicholas, is Nicholas being so closed up about his family.
- Dogged Nice Guy: He is a loving, supportive boyfriend who has to put up with so much shit from his boyfriend.
- Extreme Doormat: He can't bear the thought of not being liked. In "Maggots", he spends the whole episode stewing when Nicholas tells him that there are times when he doesn't actually love him. In "Banded Agriope Spider", he finally gets fed up with Nicholas' insensitivity and dumps him... only to try and reconcile with him in the season finale.
- Promoted to Parent: He finds himself pressed into service as Nicholas' co-parent.
- Sad Clown: In season 2, he still tries to be cheerful and friendly, but he's got a huge tuition bill to pay off (and can't really work, because he's a dentist and the pandemic is still going on), he's confined to the Moss home where he frequently butts heads with Genevieve, and his parents are getting divorced and he can't be with them because of the shelter-in-place order. He spends a lot of time trying to work out his anger by swimming, but that only goes so far. In "Cave Cockroaches", he finally snaps at Nicholas, annoyed that Nicholas waited two weeks to ask him how he's feeling about his parents' divorce, and only finally asked because he had nobody else to talk to. In "Agriope Banded Spider", he reaches his limit and dumps Nicholas.
- Played by: Hye Yun Park
The special-ed teacher at Matilda and Genevieve's high school.
- Butch Lesbian: Her short hair and stocky build are kind of a dead giveaway.
- Ignored Expert: Throughout season 1, she tries to warn Nicholas that Matilda is not ready for college away from home. Nicholas does not listen to her, and as a result, Matilda's trip to New York City ends up traumatizing her.
- Shipper on Deck: Played with. On the one hand, she gladly helps Drea ask Matilda to the prom, rallying the other students to help Drea with her "promposal". On the other hand, she is less thrilled by them actually dating, as it is distracting them from their schoolwork at a time when Matilda is supposed to be preparing for graduation.
- Played by: CJ Jones
Alex's elderly, deaf father. In season 2, he divorces Alex's mother, adding a new stressor to Alex's life.
- Awful Wedded Life: He deeply regrets being married to Alex's mother for so long, saying that he just spent years making compromises for her and in the end, they remained incompatible.
- Played by: Vico Ortiz
Alex's best friend, a biologist who apparently specializes in mole rats.