History Main / WeUsedToBeFriends

* ''Machinima/RedVsBlue'':

* ''Film/OutlawKing'': [[UsefulNotes/RobertTheBruce Robert the Bruce]] and the future [[UsefulNotes/TheHouseOfPlantagenet Edward II]] were implied to be childhood friends and were somewhat friendly towards each other until Robert renewed the Scottish rebellion against Edward I.

* ''Film/Becket'' centers around the falling out that occured between [[UsefulNotes/HenryTheSecond King Henry II]] and [[UsefulNotes/ThomasBecket Thomas Becket]] once Becket was named Archbishop of Canterbury and then decided his loyalty had to be to the church and not Henry.

* ''Series/{{Smallville}}'': [[{{Superman}} Clark Kent]] and ComicBook/LexLuthor, who go from close friends to [[ArchEnemy Arch Enemies]] over the course of the show, while the breakup of their friendship is an obvious ForegoneConclusion throughout the earlier seasons.

* WeUsedToBeFriends: Downplayed, but Ben and Howard knew each other casually and played poker a few times before Ben became a wanted murderer and Howard decided to collect the bounty. Howard firmly denies that this trope is at play.

* WeUsedToBeFriends/RealLife

[[folder:Comic Books]]
* In the ''ComicBook/New52'', ComicBook/{{Aquaman}} and his brother Orm (Ocean Master) are portrayed as having been very close as teenagers, and when Arthur left the throne, Orm begrudgingly took his place. The relationship deteriorated when Orm attacked the surface world in ''ComicBook/ThroneOfAtlantis'', forcing the Justice League into action, thus forcing Arthur to pick a side (he was talking both sides down). Afterwards, once Orm is imprisoned, they still don't particularly hate each other, but it's just the way it has to be.
* ''Franchise/XMen'':
** Depending on the mythos of that universe -- and DependingOnTheWriter -- Charles Xavier and Erik Lensherr (Professor X and Magneto, respectively) started out as best friends and bosom buddies, until they broke off because of differing opinions (Charles with the opinion that mutants and humanity are not enemies and Erik believing they are with mutants poised to become the dominant force).
** In at least ''one'' universe, the 'bosom buddies' business caused (or at least helped) both of their respective marriages to break up. This has not helped the people who protest the HoYay between the two ''at all''.
** The Juggernaut and Black Tom Cassidy, thanks to Juggy's HeelFaceTurn.
** Colossus and Magik. Especially after he sacrificed everything (including his humanity and the love of Kitty Pryde) to save her from evil by taking on the power of Juggernaut only to find that she encouraged him to become the Juggernaut because he still loved her and she wanted to show him what it was like being damned so he could understand her. At the end of ''ComicBook/AvengersVsXMen'', Peter told Illana, "If I ever see you again, I will kill you." They have since made amends and are back to being a family.
** ComicBook/{{Wolverine}} and ComicBook/{{Sabretooth}}, for apparently [[WeAreAsMayflies over a hundred years]]. But then Wolvie got Creed's girlfriend killed, taking away his happy ending, and Creed swore to dedicate his life to making sure Logan would never get one of his own.
* ''Franchise/SpiderMan'':
** Peter Parker and Harry Osborn. Their rivalry took place in the aftermath of the death of the original ComicBook/GreenGoblin, Harry's father, and led to Harry going crazy and becoming the second Green Goblin. That a boobytrap set for Peter almost killed Harry's ex-girlfriend ComicBook/MaryJaneWatson probably was seen by him as a positive side-effect.
** ''ComicBook/UntoldTalesOfSpiderMan'': As shown in ''Amazing Fantasy'' #17, Peter was actually close friends with Liz, Jason, Sally, and Tiny when they were all children, but as they got older and they began showing different interests from him they gradually drifted apart, which finished happening around the time Flash started becoming the popular "cool" kid.
** DependingOnTheWriter, this can also apply to [[{{ComicBook/GreenGoblin}} Norman Osborn]], [[{{ComicBook/DoctorOctopus}} Otto Octavius]] and Curt Connors. Both for their respective relationships with Peter and each other.
* ''ComicBook/{{Deadpool}}'' goes through this with Emily Preston. When she was killed on a mission, her consciousness was stored within Deadpool until she could get a new body, which is where their bond really started to form. Deadpool became very attached to her, and sub-consciously didn't want her to leave. After she goes into her robot body, she awakens to see that Deadpool has left. She's told he ran off, and they theorize he did such because he was upset about losing her after everything else he'd been through, and embarrassed that he could have hurt her. Throughout vol 3, they were very close, with Preston adopting Wade's daughter, Ellie. Once vol 4 started, things became more strained with them. As time wore on, Deadpool finds himself on the wrong side of a war in ''ComicBook/SecretEmpire''. [[spoiler: He ends up killing SHIELD agent, Phil Coulson -on order from Captain America, who's been cosmic-cubed into a Hydra agent. The recent chapter shows a flashback where Preston and Deadpool are heading to Coulson's safe-house to find him. Preston, unaware of what happened, asks Wade why he needed to see Coulson the other night. Wade lies about the reason, and continues to lie and play dumb so that Preston doesn't know what he did. But, she founds out and punches Wade, telling him that Ellie also loved Coulson. Preston gives Wade a brutal beating and says she thought up a way to kill him due to him not being trustworthy, given his weak-mind -which she felt someone may control at some point. Deadpool blows them both up with a grenade and destroys Preston's LMD body. Before being destroyed, she tells Wade he will burn in Hell. Wade sadly agrees and rips out her power core. He stares down at her body sadly before boxing up the parts and shipping her somewhere.]] Preston admits to hating Wade in 2099, but also reveals that she forgave him because hatred destroys a person. So their friendship is restored sometime in the future, but it's broken at this point.
* In ''ComicBook/AvatarTheLastAirbenderTheRift'', General Old Iron and Lady Tienhai were friends until General Old Iron tried to kill the humans.
* ''Franchise/{{Superman}}'':
** ''ComicBook/HowLuthorMetSuperboy'' reveals Pre-Crisis Superman and Lex Luthor were friends when they were young. Then a lab accident occurred, which ComicBook/{{Superboy}} saved Lex from. Nonetheless, Lex blamed Superboy for the fire which destroyed his most important experiment, and the rest is history.
** In ''ComicBook/SupermanVsTheAmazingSpiderMan'', when Superman confronts Lex, he brings up their old friendship.
--->'''Superman:''' We were friends once, Luthor... long ago. For a time, I hoped we could be friends again – Maybe we will be, someday – but in the meantime, we are enemies, because you chose lawlessness, and I chose law!
** In ''ComicBook/WarWorld'', Comicbook/MartianManhunter warned Superman that if he took another step closer to a crypt J'onn was tasked with guarding it might mean the end of their friendship. Superman didn’t listen and J'onn attacked him. Later Clark endeavored to retrieve an artifact stolen from that crypt in hopes of being forgiven by J'onn. [[spoiler:His fellow Leaguer eventually did so]].
--->'''Martian Manhunter:''' I gave you fair warning, Superman — a good deal more warning than I would have given anyone else! I did so because you were my friend — but the bonds of friendship can only be stretched so far before they break!
** At the start of ''ComicBook/NewKrypton'', ComicBook/{{Supergirl}} broke up with her childhood friend Thara Ak-Var when [[ComicBook/WhoIsSuperwoman she was tricked into believing]] that Thara aided and abetted her murderer's father. In ''ComicBook/TheHuntForReactron'', they reconcile after a fashion, but their friendship was still strained for a while.
** In the ''Post-ComicBook/{{Flashpoint}}'' continuity, Supergirl befriended Siobhan "Silver Banshee" Smythe shortly after arriving in Earth. However she broke it off when she thought Siobhan was using her. When they meet again during the events of ''Comicbook/RedDaughterOfKrypton'', they fought. Siobhan blamed herself for their friendship's end, but after a while Kara blamed herself for ruining it. In ''ComicBook/{{Crucible}}'', Kara listens to Siobhan's music from afar as regretting their friendship's ending.
--->'''Supergirl:''' "Someone playing music a mile away. I know that song! It's Siobhan's! At least I still have your music... Nothing's the same without you. Here I am trying to fit in on this planet, and I've lost the first friend I ever [made.]"
** ''ComicBook/ElseworldsFinestSupergirlAndBatgirl'' gives two instances:
*** Supergirl regarded Luthor as a kind of father figure... until she learned that [[spoiler:he murdered her baby cousin]].
*** Likewise, Luthor and Hamilton's friendship broke off because Hamilton felt guilty for helping Luthor [[spoiler:murder a baby and wanted to expose him]].
** Zigzagged in ''ComicBook/SupergirlCosmicAdventuresInThe8thGrade''. Linda and Lena are friends. When Lena finds out that Linda is Supergirl, she breaks their friendship off and tries to kill Linda. Then she loses her memories and they are friends again. Then she gets them back and goes back to want to kill Linda. At the end, she lets her hatred go. On Linda's side, though, she never stops from considering Lena her friend.
--->'''Supergirl:''' Lena... I'm still me! I'm your best friend!\\
'''Lena:''' Not anymore... Not now that I know the truth! You're my enemy now. I have no choice but to destroy you!
** ''ComicBook/LastDaughterOfKrypton'': Jor-El and Zor-El got along well with each other until Jor-El found out that his big brother was involved in the creation of the biological weapons of mass destruction known as the Worldkillers. Jor-El asked Zor-El to stop his experiments, and his brother responded by getting mad and refusing to talk to Jor-El and his family again.
** ''ComicBook/SupermanVsShazam'': When Captain Marvel is assailed by the Sandman Superman posing as the real Kal-El, Billy believes he must consider their friendship broken.
--->'''Captain Marvel:''' Sorry about this, Superman! We were friends once-- but not any more!
** In ''ComicBook/TheStrangeRevengeOfLenaLuthor'', Lena is so angry when she discovers that Supergirl kept her brother's identity from her that she breaks their friendship. At the end of the story, Supergirl wonders whether Lena will ever forgive her, but it is not revealed if she did.
--->'''Lena Thorul:''' Now I know the secret you've been keeping from me-- that Lex Luthor, one of the world's most monstrous criminals... is my brother! We were friends... I trusted you... But you betrayed me! Now get out of my sight, Supergirl... GET OUT!
* ''Franchise/{{Batman}}'':
** Harvey Dent was a friend of Batman and one of the first people of authority to support him, but after an incident which caused his transformation into Two-Face, the two become enemies. Notably, Batman is lighter in his dealings with Dent compared to his other villains.
** Bats and Thomas Elliot/Hush have this going as well. The two were childhood friends, but Tommy's mother would constantly tell him to be more like Bruce, which annoyed him. Eventually, Tommy tried to murder his own parents (his father was abusive) and gain their fortune, but Bruce's dad saved Tommy's mom, which he never quite got over. When Bruce's parents later died, Bruce went around travelling the world and living the life Tommy wanted to live, while Tommy was stuck at home caring for his now frail mother. After his mother tries to cut Tommy off from the fortune, Tommy kills her. He leaves for med school and to travel the world soon after, and when the Riddler eventually tells Tommy that Batman is Bruce Wayne, he tries to ruin his life on a consistent basis.
* In ''ComicBook/AllFallDown'', the Pantheon tries to reason with [[spoiler:Pronto]] this way. They don't quite succeed.
* [[ComicBook/CaptainAmerica Steve Rogers]] and [[ComicBook/IronMan Tony Stark]] in ''Comicbook/CivilWar'', which was basically portrayed as a particularly volatile break-up/divorce. With Steve [[DeathIsCheap coming back from the dead]], their relationship has since improved, not a little because fighting each other tore them both up pretty badly in the first place.
** And again during ''ComicBook/TheAvengersJonathanHickman'', when Steve realises Tony reformed the Illuminati, and then wiped his memory about it. The last arc of the run, ''ComicBook/TimeRunsOut'', involves Steve relentlessly pursuing Tony over everything else, including the imminent end of all existence.
** This has been going on ''long'' before those two events. Back during the ''ComicBook/ArmorWars'', Tony was attempting to get into the Vault to shut down the Guardsmen using his tech. Steve, here operating as The Captain, tried to come between them, but when a Guardsman begins suffocating and Steve goes to help him, Tony stuns Steve so he can disable to the last armor. Tony knows doing that damaged their friendship.
* John Walker, a former Captain America and current [=USAgent=], was once a member of the Bold Urban Commandos alongside Battle Star, Left-Winger and Right-Winger. When the US Government decided to only take John and Battle Star, Left and Right were so furious at this that they opted to reveal John's identity, leading to John's parents getting murdered at the hands of the PoliticallyIncorrectVillain group the Watchdogs. The end result leads to John pummeling the two to a pulp and leaving them to die in a burning oil refinery.
* ''ComicBook/{{Watchmen}}'': Rorschach and Nite Owl II/Dan who were crime fighting buddies before the novel, now share a tense relationship. Rorschach even somewhat disdains Dan's lifestyle, but as the story progresses they partly rebond and face the BigBad together.
* The eponymous character of ''ComicBook/TheMightyThor'' and his adopted brother, Loki, of the CainAndAbel variety.
* Subverted in ''Franchise/GreenLantern'' storyline ''ComicBook/WrathOfTheFirstLantern'' with Sinestro and Hal Jordan. Hal asks Sinestro if they were ever truly friends. Sinestro responds with, "That's the tragedy of all this. We'll always be friends."
* ''Franchise/ArchieComics'':
** ''ComicBook/AfterlifeWithArchie'' presents Veronica's and Betty's relationship as this. Veronica and Betty were friends in middle school until Archie came to town. After that Veronica's AlphaBitch personality became directed at Betty. They usually hate each other.
** ''ComicBook/ArchieComics2015'':
*** Josie and Alexandra were childhood friends until middle school, when they drifted apart and Alexandra turned mean. According to Josie, it was because Alexandra was too spoiled and selfish to handle it when Josie made other friends that wasn't her — but according to Alexandra, Josie was mainly friends with her because she was rich and "the minute I couldn't buy you some talent you bailed on me like Hollywood after an actress turns thirty."
*** Reggie and Archie, if ''Reggie and Me'' is any indication, were good friends when younger, but a near-drowning incident combined with Betty's suspicion of Reggie led to their friendship souring.
* ''ComicBook/InjusticeGodsAmongUs'' shows that Batman and Superman used to be very close, enough so that Superman asked Batman to [[spoiler: be his unborn son's godfather.]] Unfortunately, when [[spoiler: the Joker broke him,]] Superman's increasingly-rapid fall down the slippery slope eventually culminated in [[spoiler: Superman breaking Batman's back, ending the World's Finest once and for all.]]
* Franchise/TheFlash III (Wally West) and Reverse-Flash II/Zoom (Hunter Zolomon) used to be friends. Hunter was a police profiler who met Wally when he'd already been the Flash for a few years, and Hunter had a bad knee. Hunter's knee was shot by a B-list Joker knock-off early in his career due to a bad call he made, which caused the death of his father-in-law, Hunter's divorce from his wife Ashley, and his firing from the FBI. Hunter liked Wally because he had a public identity and was an open-book, while Wally liked Hunter because Hunter reminded him of his dead mentor Barry Allen (The Flash II). Eventually, Hunter's spine was damaged by Gorilla Grodd, which Wally blamed himself for. Hunter lost his ability to walk, and asked Wally to use the Cosmic Treadmill to go back in time and stop him from making his bad call with the FBI. Wally refused, citing examples like the villain Professor Zoom (Reverse-Flash I) as to why time travel is dangerous and unpredictable. Hunter says Wally refused because he has never experienced personal tragedy, and later tries to use the treadmill himself which ended up giving him time-based powers which effectively gave him superspeed (though he can't time-travel). With his new powers, Hunter decided that in order to make Wally a better hero, he must give Wally not only a great villain to face (which is why he took up the Reverse-Flash moniker), but also as much tragedy as possible. Hunter never outright tries to kill Wally, since this would defeat the purpose of why he does what he does, and Wally still feels responsible for Hunter's fall from grace.
* ''ComicBook/DruidCity'': Jack and Hunter. In the backstory, Hunter and Jack were colleagues, roommates, and fast friends. After Hunter betrayed Jack's trust to get the jump on submitting a groundbreaking article, all of that changed. In the present storyline, Jack is presented as a rather justified antagonist. The two characters are still willing to talk things out over the course of the series, but the point of each interaction is ultimately one-upmanship.
* In the ''[[ComicBook/MyLittlePonyFiendshipIsMagic Fiendship is Magic]]'' tie-in comics based on ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', Sombra punishes his only childhood friend for what he saw as betrayal by making her home town ''vanish'' while she was away.
* Adam Brashear, the Blue Marvel, and Connor Sims, the Anti-Man, were once war buddies who wound up assigned to the same super-science project, which ended up going wrong and giving them superpowers. However, Connor's powers ended up driving him insane, which eventually resulted in the death of Adam's wife Candace. [[ComicBook/TheUltimates2015 When they meet again]], the normally good-natured Adam is furious at seeing him, even though Connor can't remember what happened.
* In ''ComicBook/SwordquestRealworld'', Peter and Alvin were best friends growing up, and almost became more than friends, but it was the 1980's and Alvin chose to become an ArmoredClosetGay instead. Peter never forgave him for this, especially not after Alvin ended up publicly coming out of the closet years later in a cynical attempt to avoid getting kicked off of a reality TV show.
* In IDW's ''Franchise/{{Transformers}}'' comics, BigBad Megatron [[FromNobodyToNightmare started out as a miner]], working alongside Impactor, who would later join the Autobots. At one point Impactor manages to buy himself an extension to his life by telling a marauding Megatron "Not more of your poetry," causing Megatron to back down rather than kill his old friend.
* ''Franchise/WonderWoman'':
** ''ComicBook/WonderWoman1987'': Veronica Cale had one person, and one person only ouside of her deceased mother, that she cared about; her best friend Leslie Anderson. When Anderson starts to grow to like and befriend Wonder Woman and then uncovers Cale's fairly diabolical and pettily motivated plot Cale allows her to live, but threatens her into keeping her mouth shut and cuts her ties with Anderson by manipulating things so that if Cale's actions come to light all of the clues will lead back to Anderson as the mastermind instead.
** The revamped ComicBook/{{Cheetah}} from ''ComicBook/WonderWomanRebirth'' was Diana's friend before being tricked into thinking Diana had betrayed her and led into the painful unwanted transformation which gives her her powers.
* ''ComicBook/TheSandman'': As seen in ''Endless Nights'' (which is set a long time before the main events), Dream and Desire of all people used to be quite close, with Dream referring to Desire as his favorite sibling. Then Desire meddled with one of Dream's love affairs, and it messed up their relationship ever since.
* ''ComicBook/BlakeAndMortimer'': Mortimer and Sushil were best friends since childhood. By the time Mortimer returned to India from his studies, Sushil had changed greatly and joined an Indian extremist group, having grown to consider Mortimer his enemy, but the feeling is one-sided as Mortimer still sees Sushil as his friend.
* In ''[[ComicBook/EmmieAndFriends Remarkably Ruby]]'': Ruby and Mia, the two narrators, used to be close friends but as Mia became popular and made new friends, she started to push Ruby away from her--especially after Ruby started middle school behind her and her awkwardness kept embarassing Mia. [[spoiler:It's also hard on Ruby--and their parents--because the two are sisters.]]
[[/folder]]

** The main participants of the Dance of the Dragons, Rhaenyra Targaryen and her stepmother Alicent Hightower, were initially close, as Rhaenyra welcomed a motherly presence in the court after the death of her own mother. But then Alicent gave birth [[HeirClubForMen a son]]...

** And again during ''ComicBook/JonathanHickmansAvengers'', when Steve realises Tony reformed the Illuminati, and then wiped his memory about it. The last portion of the run involves Steve relentlessly pursuing Tony over everything else, including the imminent end of all existence.

** In ''ComicBook/SupermanVsTheAmazingSpiderMan'', Superman brings their old friendship up when he confronts Lex.

* Ian and Greg, Sara and "The Libbys", also Madison and Ashley in ''Literature/TotallyHigh": According to Ian, him and Greg used to be friends since they're were ten years old and their friendship only last up to eight grade. Since freshmen year, Greg was cool of being popular and cute football player at Mickinley High including hanging out with the popular crowd instead with Ian. Greg had his fame and populairty goes all on his head and he pretty TookALevelInJerkass when it became like that and abandoned his loser friend. He bullies the nerds, the unpopular kids and the saddest part is, He even bullies Ian.
** Sara used to be friends with the libbys and mainly to Chanel. Until Sara had glasses which she couldn't be able to see, so her friends cut her off for good. She became a HollywoodNerd ever since.
** Maddison and Ashley used to be friends, until the snowflake queen votes that caused to end their friendship. so Madison won at that time, so her and Ashley hated each other.

Contrast with HeelFaceTurn. Compare with AchillesInHisTent, DeusExitMachina, MyGreatestFailure, GreyAndGrayMorality and JumpingOffTheSlipperySlope, EvilFormerFriend, BreakingTheFellowship, EtTuBrute. See also CainAndAbel, when the former friends in question were either siblings, or were childhood friends who grew up with each other prior to their falling out. See FormerlyFriendlyFamily for more then just siblings that grew to hate each other. For the inversion, see also FireForgedFriends: enemies-turned-allies.

[[caption-width-right:310:"You were my ''brother'', Anakin! [[PlatonicDeclarationOfLove I loved you...]]"]]

[[folder:Western Animation]]
* ''WesternAnimation/{{Amphibia}}'': Anne Boonchuy and Sasha Waybright used to be best friends until Anne discovered how controlling Sasha was towards her, resulting in them drifting apart. Despite this the two still care deeply about each other with Anne vowing to find her and make things right.
* ''WesternAnimation/{{Arcane}}'':
** Though more emphasized in the [[AllThereInTheManual accompanying]] MV [[https://www.youtube.com/watch?v=F5tSoaJ93ac Enemy]], Ekko was close friends with Powder and her adoptive family. [[spoiler: They became intractably pitted against each other as Powder becomes [[MadBomber Jinx]]. Flashbacks to Ekko and Powder happily playing as children with wooden sword and paintball gun play right before Ekko attacks Jinx with a metal pipe while she's trying to nail him with real bullets. He ultimately can't finish the beating because of his memories.]]
** Silco and Vander used to close enough to refer to each other as brothers, but by the present, both of them are at odds with each other, especially considering Vander's attempt to murder him, and Benzo similarly doesn't take kindly to seeing him again.
* ''WesternAnimation/AvatarTheLastAirbender'' reveals that Aang's predecessor Avatar Roku used to be best friends with Firelord Sozin, the man who started the [[TheEmpire Fire Nation's]] war for world domination, and committed genocide against the Air Nomads.
* As Ethan Bennett/Clayface is an {{expy}} for Two-Face, he and Bruce had this in ''WesternAnimation/TheBatman'' between having Ethan's breakdown over how people saw him in "Meltdown" and his redemption in "Clayfaces", with Bruce being upset in the former episode that his attempts to help his friend failed, treating him as an outright villain in [[spoiler:"Grundy's Night"]], and being concerned when Ethan returns in "Clayfaces".
* ''WesternAnimation/BoJackHorseman'':
** In Season 1, [=BoJack=] and Herb Kazzaz. The latter never forgave [=BoJack=] for not coming to his aid when he was blacklisted from the entertainment industry [[spoiler:for being gay.]]
** Season 3 ends on a particularly friendless note for [=BoJack=]. [[spoiler:Todd has had it with [=BoJack=]'s selfish, self-destructive behavior and gives him a TheReasonYouSuckSpeech in the third-to-last episode of the season. [=BoJack=] has fired Princess Carolyn as his agent. Things are weird between him and publicist/occasional lover Ana Spanakopita. Add to his former co-star/friend/sometime lover Sarah Lynn overdosing in his arms in the second-to-last episode, and [=BoJack=] is in a really bad way as far as friendships go.]]
** The series finale features [[spoiler:Diane making a clean break from Bojack.]]
* ''WesternAnimation/BraceFace''. Sharon and ArchEnemy Nina Harper used to be real good friends until the second grade, when someone mysteriously chopped off the heads of Nina's dolls and she blamed it on Sharon.
* ''WesternAnimation/CodenameKidsNextDoor'':
** The second-to-last episode of the show, "Operation: T.R.E.A.T.Y.", shows that Numbuh 1 and the former Numbuh 274, Chad Dickson, used to be quite close. Chad had apparently mentored Nigel back when he was a cadet, and Nigel was close enough to him to call him "old friend". Thus, Chad's betrayal was a cut so deep that the two developed a huge rivalry that lasts the rest of the series. It eventually boiled down to this episode, where a ChainedHeat situation strains their already tenuous relationship to the breaking point, and by the end, they're trying to kill each other. [[spoiler:Even after it's revealed that Chad was a FakeDefector, his disappearance afterwards and his behavior throughout the episode makes it evident that the bridge is burnt and that there's no salvaging their friendship]].
** Numbuh 5 and Heinrich Von Marzipan were once good friends and [[AdventurerArchaeologist partners in candy hunting]]. An [[NoodleIncident incident in Guatemala]] destroyed their relationship and resulted in Heinrich having a deep hatred of Numbuh 5. Eventually it was explained in the episode "Operation: C.A.R.A.M.E.L." that [[spoiler:Heinrich was originally a girl named Henrietta who, during an adventure she and Numbuh 5 were on, fell victim to a curse that [[GenderBender took away her femininity]] [[ItMakesSenseInContext in exchange for magical caramels]]. Some urgent business came up and Numbuh 5 was forced to leave Henrietta (now Heinrich) alone. Heinrich blamed Numbuh 5 [[NeverMyFault for not stopping him from eating the caramels]], and believed the curse became permanent as a result. But Numbuh 5 had secretly kept one caramel, which she would use to help Heinrich break the curse and turn back into a girl. [[HeelFaceTurn Henrietta]] and Numbuh 5's friendship was then restored.]]
* WesternAnimation/DaffyDuck gives WesternAnimation/BugsBunny mad ups in "WesternAnimation/PorkyPigsFeat." When they get paired up over ten years later, Daffy becomes the Iago to Bugs' Othello.
* In ''WesternAnimation/{{Gargoyles}}'' this occurs between Macbeth and Demona, as seen in "City of Stone": best of friends when they first fought together against Duncan and won Macbeth his kingdom, things go south when Demona, mistakenly believing that Macbeth was about to betray her and her clan, betrays him first, causing him to lose his kingdom, family, and identity.
* ''WesternAnimation/GravityFalls'': [[spoiler:Ford]] used to be close friends with both [[spoiler:Stan and Bill.]] But external circumstances have him falling out with them:
** For the latter, [[spoiler: Ford was lulled by Bill's flattery, believing that Bill was a muse looking to inspire a brilliant mind. It broke after he realized that the demon only used him to create a portal to enter Gravity Falls and remake the world in his image.]]
** [[spoiler:Stanford's relationship was torn with his brother when Stan accidentally ruined his chance to go to his dream college. Ford continued to hold resentment for the accident for the next forty years despite Stan working hard to bring him back, and insists that Stan gives his identity and house back, and quit the Mystery Shack business for good, mutually disowning each other as the latter declares the kids to be the "only family" he has left. Luckily, the older twins reconcile after the events of Weirdmageddon after realizing that they were both petty towards each other.]]
** [[spoiler: Ford was also college buddies with Fiddleford [=McGucket=], and the two collaborated on Ford's portal until an accident saw [=McGucket=] learn the full scope of Bill's plan and leave in terror, eventually causing his SanitySlippage.]]
* In ''WesternAnimation/JusticeLeague'', after Shayera was exposed as a mole for the Thanagarians, she was welcomed back into the League, but Wonder Woman felt betrayed and held a grudge for some time, refusing to speak to her. It got so bad at one point, Flash tried to step in and patch things up between the two. It took the two of them being forced to work together to stop Felix Faust from usurping Hades' throne in order to settle their differences.
* Played with in ''WesternAnimation/BatmanBeyond'' when "Big Time" Bigelow, one of Terry's old buddies from his delinquent years, gets released from prison and tries to reconnect with him. Terry is conflicted and wants to trust and help the guy since they used to be friends, while Big Time pretty much completely focused on himself and views Terry as an accomplice at best. It takes a couple of episodes for Terry to accept that the guy is BeyondRedemption and, unlike he who honestly was just a "stupid kid who made some bad mistakes", a genuine criminal through and through who can't be helped since he won't help himself and [[FalseFriend couldn't care less about Terry beyond what he can use the guy for]].
* Jacob and Kane (along with Dr. Hudson, although he's not really a bad guy) in ''WesternAnimation/{{Motorcity}}''. Jacob now fights [=KaneCo=] with the Burners and helped design their bots, which gives him some inside knowledge.
* In ''WesternAnimation/KimPossible'' episode "Attack of the Killer Bebes", Kim's father Dr. James Possible tells her a story about how in college one of his friends Drew Lipsky offered to get dates for their group, but instead of live women, built a bunch of clunky robots. The gang thought that this was patently ridiculous and laughed at Drew for days, after which Drew dropped out of college and disappeared entirely. The end of the episode reveals that Drew Lipsky became ''Dr. Drakken'', Kim's arch-foe, and his turn to evil descends from the betrayal and resentment he felt for the disrespect he got from his "posse".
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'':
** The Alicorn sisters Princess Celestia and Princess Luna used to jointly rule Equestria together until Luna became bitter and resentful when their subjects favored Celestia over her, turning her into Nightmare Moon. After Luna is defeated and returned to normal centuries later, however, the two sisters reconcile.
** Rainbow Dash and Gilda in "Griffon the Brush Off". They used to be childhood friends, but their friendship is broken off after Dash finds out that Gilda has been bullying her other friends behind her back. This bitterness carries over into their reunion in "The Lost Treasure of Griffonstone", though Pinkie Pie proves that Gilda has a [[JerkWithAHeartOfGold heart of gold]] and helps them make up in the end.
** Discord attempts to invoke this in the two-part season 2 premiere "The Return of Harmony" in order to keep them from using the [[ThePowerOfFriendship Elements of Harmony]] against him, using a combination of [[{{Brainwashed}} mind control]] and [[MoreThanMindControl mind tricks]] to get Twilight's friends to behave opposite of their respective elements. [[NearVillainVictory He very nearly succeeds]] in pushing Twilight over the DespairEventHorizon with her corrupted friends, but Twilight overcomes his mind games with help from her old friendship reports and lifts his spell on her friends to take him down.
** In "Amending Fences", Twilight is shown to have drifted so far apart from her old friends at Canterlot that she can't even remember their names. As soon as this dawns on her, [[MustMakeAmends she immediately sets out to fix things]]. While most of them are [[TurnTheOtherCheek willing and eager to reconnect]], her closest friend Moondancer wound up holding a deeply seated grudge because Twilight brushed off her one attempt to be more social and then left without saying goodbye, which caused Moondancer to isolate herself in her books and studies much like Twilight herself used to do. After Moondancer [[TheReasonYouSuckSpeech finally vents her pent up frustrations at Twilight]], the two patch things up.
** At the end of [[Recap/MyLittlePonyFriendshipIsMagicS8E26SchoolRazePart2 "School Raze"]], [[spoiler: everyone [[FaceOfAnAngelMindOfADemon Cozy Glow]] has ever [[FalseFriend "befriended"]] and exploited is no longer fooled by her innocent act [[HatedByAll and turns against her]]]].
* Amity and Willow from ''WesternAnimation/TheOwlHouse'' were best friends when they were children before Amity spontanously ended their friendship because Willow's magic was weak. [[spoiler:Or at least, that's the excuse that she gave. In reality, [[AbusiveParents Amity's parents]] disapproved of Willow and threatened to prevent her from attending magic school if Amity didn't cut ties with her immediately. Once the truth comes to light, they slowly start to rekindle their friendship.]]
* The King of Galaluna and Modula in ''WesternAnimation/SymBionicTitan''. Lance's WholeEpisodeFlashback shows them getting along amicably but most of the show is Modula [[DistressedDude holding the King hostage]]. The King is surprised when he discovers Modula was behind his planet's invasion.
* In ''WesternAnimation/{{Recess}}'', T.J. and [[spoiler:[[TeachersPet Menlo]], of all people]] used to be friends. [[spoiler:However, even though they don't hang out anymore, they made an agreement that T.J. would come to Menlo's birthday party every year.]]
* ''WesternAnimation/SheRaAndThePrincessesOfPower'' has former best friends Adora and Catra. The series starts out with both of them as soldiers in [[TheEmpire The Horde]], having grown up together as orphans raised in the military group. Adora learns the true nature of the Horde shortly after being promoted to force captain and defects to the rebellion, with Catra angrily rejecting the offer to join her. Later on, in "Promise", Catra explains in greater detail why she doesn't want to join the rebellion despite both of them knowing that she doesn't necessarily agree with what the Horde is doing: she's [[AlwaysSecondBest always been second best]], trapped in Adora's shadow for as long as she can remember, suffering abuse and constantly being underestimated. Given the choice between continuing to work for the bad guys and finally getting all the respect, recognition, and power she's always wanted in life now that Adora is gone, and working for the good guys where she'll again find herself {{overshadowed by awesome}} at very turn by both Adora and her cavalcade of magic princesses, she's going to stick with the former.
** It doesn't happen as often, since they weren't as close originally and don't run into each other as often, but Lonnie - who was in the same squad as both of the above - has also been known to bring up their former friendship when she and Adora face off.
* ''WesternAnimation/TheSpectacularSpiderMan'':
** Over the course of season 1, [[ComicBook/{{Venom}} Eddie Brock]] and Peter Parker go from being bros to mortal enemies. An entire seasons worth of Peter apparently betraying Eddie and everyone around them for personal gain and Peter becoming a selfish aggressive jackass because of the Symbiote was already enough to fizzle that friendship for good, but then the Symbiote got onto Eddie and [[EvilFormerFriend just made things even worse]]. It's made even more depressing for poor Pete that most ([[MomentOfWeakness though admittedly not quite all]]) of said "betrayals" were actually Peter saving everyone as Spider Man. [[BeingGoodSucks Great responsibility sucks sometimes]].
---> '''Mary Jane:''' I know you got a lot on your mind, but me and Eddie went out on a date. He only asked me out because he thought you and I were a thing. He wanted to ''hurt'' you, and he didn't mind using me to do it.
---> '''Peter:''' Well... it has been pretty rough between us but, I, no, no! He's still my bro!
---> '''Mary Jane:''' Be careful, Tiger. I don't think he's your bro anymore.
** Peter and [[JerkJock Flash Thompson]] of all people were best friends in nursery school. It was even revealed that it was the former who coined the latter's nickname. And no, [[NakedPeopleAreFunny it wasn't because he could run fast.]] When this was revealed at the latter's party, ''everyone'' present is shocked.
* Plankton and Mr. Krabs of ''WesternAnimation/SpongeBobSquarePants''. They used to be best friends much like [=SpongeBob=] and Patrick, but are now mortal enemies because of the Krabby Patty formula.
* ''WesternAnimation/StarVsTheForcesOfEvil''
** The ''Deep Trouble'' comics show that a falling out with Star was the in-universe reason for Alfonzo Dolittle & Ferguson O'durguson being DemotedToExtra in Season 2 -- Star stopped taking them with her and Marco on adventures because of their immature behavior. She gets even more reason to distance herself from them when she finds out that they've been breaking into her room and screwing around with her stuff, and she speaks of them rather disdainfully even before learning about that. Star's offhand line about how Marco would still be hanging out with them [[ItMakesSenseInContext if she were never born]] implies that Marco spends much less time with them. He doesn't look too happy to see that they've been breaking into his house to raid Star's room either. Finally [[SubvertedTrope Subverted]] when the episode "Sophomore Slump" reveals that Marco is still friends with them and hangs around them. Though they did get annoyed at Marco when he keeps talking about Mewni, they accept Marco's apology for his behavior and they present him with their lucky dice as he leaves for Mewni.
** Rhombulus and Star established a friendship after bonding over their shared flaws, but she comes to [[BrokenPedestal lose]] respect for him and the other Commission members upon learning that they [[UnPerson erased all records of Meteora's existence]]. And whatever leftover friendliness she had for him completely disappears [[spoiler:after he tried to frame Eclipsa for releasing Globgor]].
* The ''WesternAnimation/StevenUniverse'' episode "Maximum Capacity" reveals that Greg and Amethyst used to be good friends who enjoyed watching tapes from an old sitcom together. Their relationship is more strained now due to Amethyst's resentment over Greg monopolizing Rose Quartz's attention when they started their relationship and Greg spending less time with Amethyst as a result (leaving her feeling even more alone). Greg admits he would like them to be friends again, but not if it means he has to put up with her hurtful behavior.
* The BackStory of the ''WesternAnimation/StormHawks'' had [[TheDragon The Dark Ace]] as friend and co-pilot to the original Storm Hawk's captain. He's the reason why the original Storm Hawks [[BackstoryHorror are all dead]].
* ''WesternAnimation/TangledTheSeries'' has a rather sad example between Rapunzel and [[spoiler: Varian]]. [[spoiler: The clumsy Varian]] started out as a close friend of Rapunzel's and provided a lot of help for her, Eugene, and Cassandra with [[spoiler: his inventions]]. Then came the episode "[[WhamEpisode Queen For a Day]]", which marked the downward spiral of his and Rapunzel's friendship: [[spoiler: Varian inadvertently causes [[WellDoneSonGuy his father]] to start getting encased in crystal. In a panic, Varian travels to the castle of Corona only to find Rapunzel and the others with too many other problems on their laps (a cataclysmic snowstorm is threatening to tear Corona apart and her parents are missing) to just drop it all and help Varian out. Varian comes back to find his dad completely encased in crystal and, [[DespairEventHorizon in his anguish]], blames Rapunzel for not coming to help him. By the end of the season, Varian has slowly but surely severed almost all ties between not only Rapunzel but the entire kingdom (to the point of kidnapping the Queen), and Rapunzel is clearly hurt by this by the end of "The Alchemist Returns", admitting she "[doesn't] even know what he is anymore". Rapunzel, however, still has hope that the friendship could be salvaged, given that she asks for Varian to be treated with care and given the help he desperately needs following his arrest. Fortunately, early on in season 3, it's shown that Varian has come to regret his actions, and he and Rapunzel soon forgive each other and become friends again.]]
* Occurs in the second ''[[WesternAnimation/TeenageMutantNinjaTurtles2003 Teenage Mutant Ninja Turtles]]'' cartoon between Leonardo and the Shredder's adopted daughter Karai, who in previous seasons had developed a rapport of sorts with him, despite their FeudingFamilies. When the turtles successfully stop the Shredder's plan [[spoiler: to leave Earth to conquer the Utrom homeworld, and end up getting him imprisoned and exiled]], Karai takes it as a betrayal, and vows to avenge her father. Later, after Karai [[spoiler:destroys the turtles' lair and believes she's killed the other turtles and Splinter]], she heads into April O'Neil's shop and asks her to give Leonardo a message. When April asks Karai (whom she's never met before) how she knows the turtle, she responds with the trope name.
* The ''WesternAnimation/TinyToonAdventures'' episode "Citizen Max" shows Buster and Montana Max used to be the best of friends when they were younger, they shared whatever they had because Max was poor, then his parents won the lottery and Max became a selfish, greedy jerk and cut off his friendship with Buster.
* ''WesternAnimation/TotalDrama''
** It vaguely {{implied|Trope}} that Bridgette and Geoff's friendships with Gwen broke apart during ''Action'''s Aftermaths as a result of Gwen's breakup with Trent.
*** During ''Island'', Bridgette and Gwen were close friends, but Bridgette turned against Gwen during ''Action'', blaming her for breaking up with Trent. While Bridgette does not outright end their friendship, she makes it clear through her words and actions that she disapproves of how Gwen broke up with Trent and she was not on her side. Bridgette even told her that Lindsay and Beth are ticked at her because they found out that Trent threw their team's challenges for her. And while Bridgette disapproves of Geoff's treatment of Gwen and tries to protect her from his torture, the two girls are never seen making up or interacting again for the rest of the series (although this is partly due to Bridgette falling OutOfFocus as an early elimination on ''World Tour'' while Gwen continued to receive focus as part of a LoveTriangle with Duncan and Courtney).
*** Geoff and Gwen became friends during ''Island'', but after he TookALevelInJerkass during the Aftermath segments in ''Action'', their friendship deteriorates. While he does not outright end his friendship with Gwen, Geoff guilt trips her over her breakup with Trent, nearly drops an anvil on her, and tries to throw her in a dunk tank full of piranhas. When Gwen points out that they are friends, he responds that his new gig "trumps" the times that he and Gwen made s'mores. He also tells her that she did not leave many friends behind in the game. They never made up and do not interact for the the rest of the series (although this is partly due to Geoff falling heavily OutOfFocus and not competing at all in ''World Tour'').
** Ezekiel and Harold were friendly with each other in the first episode. However, their new friendship was halted when Ezekiel angered his whole team with his sexist comments and he was voted off with no way to keep in contact with Harold. In episode "Haute Camp-ture", Ezekiel wonders why Trent is helping Harold after he rigged the votes to get Courtney eliminated to get back at Duncan in "Basic Straining", calling Harold a traitor. This implies that Ezekiel ended his friendship with Harold off-camera because of his actions against Courtney. Later on, Harold angrily blames Ezekiel for losing the first challenge of ''World Tour''.
** Heather and Leshawna were bitter enemies in ''Total Drama Island'', and that did not change in ''Total Drama Action''. But when Leshawna's teammates learn that she pretended to have a breakdown in order to guilt trip her teammates into letting her have a night at a spa away from the set and badmouthed them behind their backs, Heather was the only one to forgive her and defend her actions. So when Heather was voted off, Leshawna tells Heather she considers them friends. In a later episode, Leshawna states that she meant what she said and she does consider Heather her friend. By season 3, Heather and Leshawna are back to being bitter enemies with no reason given why their friendship ended. In fact, Leshawna even hates Heather more, once beating Heather up for warning her about Alejandro being evil. And even when she learns Heather was telling the truth, she was still glad she beat Heather.
** In ''All-Stars'', Courtney's extremely bitter over what happened between her and Gwen in ''World Tour'', due to the entire mess of Duncan kissing Gwen behind Courtney's back. Unfortunately, even after they finally buried the hatchet, Courtney ''still'' tries to pull the rug out from Gwen when it is revealed she doesn't intend to take her to the finale as they promised; Gwen is quick to return this sentiment to her and Courtney is unable to talk her way out of elimination.
* In ''WesternAnimation/WinxClub'', after [[spoiler: Nabu]] is KilledOffForReal, Aisha decides to join Nebula's faction of Earth fairies bent on revenge, a decision the rest of the Winx cannot support, and she angrily breaks from them. [[spoiler: Doubles as a TenMinuteRetirement as she is very shortly reconciled with her friends.]]
** Lucy had been Mirta's only friend at Cloud Tower, and they had been friends for a long time, but Lucy is insecure and obsessed with gaining the approval of Icy, Darcy, and Stormy while Mirta openly questions their actions and the witches' dislike of fairies, to Lucy's ire. Their friendship ends over Lucy's desire to be part of the Trix. While Lucy sees the error of her ways when the Trix take over the school, they do not really become friends again until the next season, after Mirta has transferred to Alfea.
[[/folder]]

** In ''Film/BlackPanther2018'', Klaue and Killmonger spend a majority of the film teaming up with each other taking part in a vibranium artifact theft. It's only then that Klaue realizes what's he up against and that he had no idea he was helping the son of N'Jadaka with said theft all along. It's too late for him however as denying Killmonger the right to go to Wakanda ends up costing him his life.

** DependingOnTheWriter, this can also apply to [[{{ComicBook/GreenGoblin}} Norman Osborn]], [[{{ComicBook/DoctorOctopus}} Otto Octavius]] and Curt Connors.