Two characters are best friends. One of them makes a new friend and the other gets jealous, thinking that they might replace them.
This is what is called New Friend Envy, where the other friend feels excluded or left out more often by both of them. Most of the time, it's just a huge misunderstanding. At the climax of the plot, the other friend may reveal that they just want to branch out more and find some new people to hang out with other than the same friend all the time. Sometimes, the new friend isn't really a nice person after all or hides their true colors around them and distances them from the other.
Played for Drama if one of them ditches the other for their new friend.
- The cause of much drama during the Deathtival tournament in Killing Bites. Nodoka had just been harshly beaten up and poisoned while trying to protect her new friend Pure, who then arrives with Tasuku to help her. Nodoka, being blinded by pain and highly mentally unstable, transforms from a giant sloth hybrid to a humongous berserking megatherium and kills Tasuku in the confusion before being mortally wounded herself by a distraught Pure.
- In Love Live! Sunshine!!, after Riko transfers in, she and Chika quickly become attached. This causes You some angst as she's used to being Chika's best friend, but she's too kind to actually say anything. Eventually, Chika proves that Riko getting extra attention was only temporary while she got used to her new school and that she still cares about You just as much as always.
- An episode of Hell Girl centers around this. A girl named Minami becomes close friends with another girl named Shiori, who soon starts spending time with other new friends and shutting her out entirely. Enraged at the perceived abandonment, Minami enters Shiori's name into the Hell Correspondence. Later, Shiori finds herself in the same situation when her other friends leave her for someone else and goes back to Minami in response. It ends in tragedy when Shiori forces Minami to pull the thread on the straw doll in hopes of cursing the other girls. Since Shiori is the only one that the doll works on due to her name being entered, Minami can now only hope that they can be friends when they meet again in Hell.
- Cyber Team in Akihabara: In the early episodes, Suzume starts growing jealous of Tsugumi when the latter easily befriends Hibari, with whom she's been best friends since childhood. The two eventually overcome the animosity after some battles together.
- Pokémon: Pikachu goes through this in Episode 30 of the Journeys season, due to Ash spending much of his time training and battling with Riolu instead of him. Feeling neglected, Pikachu storms off in anger, but they make up at the end of the episode.
- Infinity Train: Blossoming Trail: Part of the reason why Chloe resents Ash so much is because of how easily he bonded with her Childhood Friend Goh. Complicating matters further is that she and Goh have been growing increasingly distant for years due to his obsessive pursuit of Mew, and the two are helping her father out with his Pokémon research, unaware of how neglected she feels.
- In Part 2 of the same story, Goh feels this way over seeing Trip and it gets worse when he learns that Ash and Trip are together as boyfriends.
- Charlie and Lola: In the book "My Best, Best Friend", Lola worries that Lotta is no longer her best friend when Lotta starts spending time with the new girl Evie.
- In the Elephant & Piggie book My New Friend is So Fun!, Gerald's best friend Piggie and Snake's best friend Brian Bat hit it off really well which causes Gerald and Snake to worry that their friends may decide that they like each other's company better than their other friends'. Their fears are dispelled when Piggie and Brian Bat show them that they drew "best friend" pictures of them.
- Fancy Nancy: In the book "Pajama Day", Nancy's best friend, Bree, befriends Clara and feels left out. It gets even worse when Bree and Nancy agree on wearing the same nightgown but Bree and Clara come to class in different matching pajamas.
- Secret Series: When Cass first befriends Yo-Yoji, Max-Ernest is jealous and thinks Cass doesn't want to be his best friend anymore. Eventually, the two boys make friends, and the conflict is resolved.
- iCarly: Exaggerated in the episode,"iReuniteWithMissy", Carly's old friend, Missy, moves to Seattle and makes Sam feel like left out and that she is going to replace her. She also believes that Missy is out to get her after sending her to a pinata factory, dropping her phone into Wahoo Punch and giving her expired chocolates, but Carly thinks that she's just jealous of Missy. She also exposes her true colors to Sam that she wants to reclaim her position as Carly's only best friend and uses "paranoia" against her after Sam gets angry at her for all of this. Freddie gives the overseas trip to Missy and she rubs it all over Sam's face that she's not going to sabotage her friendship with Carly, at which point Carly overhears this and figures out the truth of Missy's motivations, ending her friendship with her.
- House of Anubis: At the beginning of the series, Patricia, Joy, and Fabian formed a close circle of friends. Then Joy disappeared and Nina came to the school, earning Patricia's wrath - not only did she assume Nina to be connected to Joy, but she also felt jealous over Fabian becoming Nina's friend instead of hers. This would later extend to her being jealous over Nina becoming close to Amber as well.
- In Black Closet, one of the potential cases is trying to patch the friendship of two of the students that are strained, one of the variants being due to this. It can be resolved by either persuading the jealous friend, telling the new friend to back off or finding out from the jealous friend's roommate that the former plans to nonlethally Murder the Hypotenuse and putting her in detention afterward. If the case isn't solved in time the jealous girl will push the new friend down the stairs.
- In the The Amazing World of Gumball episode "The Third", Gumball and Darwin realize that their friendship has gotten boring and decide to find a third friend to liven it back up, eventually settling for Tobias. Darwin and Tobias start spending more time with each other, which makes Gumball feel left out. When Darwin goes to Tobias' house for a sleepover, Gumball refuses to come but is later convinced by Alan to go to him to save his friendship. The end of the episode reveals that Darwin missed Gumball and the two reconcile.
- In the episode "Buster's New Friend", Arthur worries that Buster isn't his best friend anymore when he starts hanging out more with a boy named Mike. At the end, Mike is revealed to be a teenager and Buster was hanging out with him as part of a Big Brothers & Sisters type program.
- In "Besties", Buster and Ladonna go to the movies while Arthur has to stay home. When they continue to share an inside joke based on their trip, Arthur gets jealous and tries to spread lies about the two. Buster and Ladonna stop being friends, and Arthur feels guilty; when he finds them both at the zoo, he is forced to be honest. However, they witness another funny event, which Arthur, Buster, and Ladonna all proceed to joke about.
- Franklin: In the episode "Franklin Goes to Day Camp", Franklin and Bear let Possum hang out with them when his best friend, Squirrel, is absent for the day due to being ill. Possum and Bear start to hang out together by joking around with each other throughout the day's activities, and as a result, causes Franklin to become jealous, and feel left out.
- In the episode "Jurassic Bark", Bender is jealous when Fry calls Seymour the dog his best friend.
- In "The Lesser of Two Evils," Leela guesses that this is what's really going on when Fry starts insisting that Flexo, another bending unit that Bender has been spending time with, is secretly evil (a somewhat moot point given that Bender is openly evil).
- Hilda: In the episode "The Nisse", Hilda and David feel like this when their friend, Frida, makes a new friend named Kelly, a Marra. They even had a secret handshake. The truth was that Kelly was keeping Frida away from her friends and from going on the Scout trip.
- Kim Possible: When Shego is temporarily turned good in "Stop Team Go", she and Kim become close friends, causing Ron to feel left out.
- King of the Hill: Bill and Dale become jealous when Hank meets a new friend, Hal, and starts hanging out with him. Their efforts to go on without Hank result in them being trapped in a rented back-hoe that's fallen into a deep hole they dug with it.
- The Looney Tunes Show: In "Best Friends Redux", Bugs Bunny receives the visit of his childhood best friend named Rodney Rabbit, which causes Bugs friend and roommate Daffy Duck to become jealous. Daffy even goes so far as to travel in time and prevent Rodney from ever meeting Bugs. This in turn creates an alternate timeline where Bugs never sent a letter to Rodney, and thus never randomly met Daffy while sending said letter in the first place, forcing the duck to go back in time and fix his mistake.
- Milly, Molly: In the episode "Sooty", when Chloe invites Milly to her birthday party but not Molly, Molly thinks Chloe is deliberately trying to "steal" Milly, but really it's because Molly was still afraid of horses at the time and Chloe owns a horse named Prince.
- Muppet Babies (2018): In "The Best, Best Friend", when Rowlf visits the playroom and impresses the babies with his piano playing, Fozzie worries that he's replaced him as Kermit's best friend. To try to win Kermit back, Fozzie challenges Rowlf to a game of Tri-Soccer Flying Baseball, a game he and Kermit invented, but Rowlf ends up winning. Fozzie then tries acting like Rowlf, but he, unfortunately, can't play the piano very well. When Fozzie tells Kermit that he feels like Rowlf has replaced him as his best friend, Rowlf tells Fozzie that Kermit told him he's still his best friend. Kermit also reveals to Fozzie that you can have more than one best friend.
- My Little Pony: Friendship Is Magic:
- In the episode "Griffon the Brushoff", Rainbow Dash meets an old friend named Gilda, a griffon, and they spend too much time with each other, making Pinkie Pie feel left out. Gilda also acts mean and disrespectful to Pinkie Pie behind Rainbow Dash's back. Pinkie Pie tells Twilight about this, but she just implies that she's just jealous of Gilda. Pinkie Pie isn't the only person Gilda is mean to; she's also like this to Granny Smith and even Fluttershy, of all people. Pinkie Pie decides to get back at her by pulling a variety of party pranks on her, which causes Gilda to finally snap. She insults everyone as well as yelling at Pinkie Pie for setting her up. In reality it was Rainbow Dash who set up the pranks. Rainbow Dash gets super disappointed at Gilda for her sour attitude towards her friends and tells her to go find some "new cooler friends" somewhere else.
- In "Make New Friends but Keep Discord", Discord is jealous of Fluttershy's new friend Tree Hugger.
- Regular Show: Downplayed in the episode "Video Game Wizards". Mordecai picks Skips to be his partner in a video game tournament with him. Rigby becomes jealous and spends most of the episode sniping Mordecai and vice versa. At the tournament, Mordecai reveals that he picked Skips instead of Rigby because he's horrible at video games, which causes him to get upset. Skips is disappointed in Mordecai and he urges him to let Rigby play in the tournament, but he refuses up until the finals when he realizes his friendship with Rigby is more important than winning the Maximum Glove.
- Star vs. the Forces of Evil: Flying Princess Pony Head arrives to visit Star, but when she meets Marco, a.k.a. "Earth Turd", she grows jealous thinking Star is going to replace her with a human.