Mushu from Mulan II spends most of the movie trying to break up Mulan and Shang. It was all just because the ancestors did the same, threatening to separate him from Mulan and give him back his old job of gong ringer if she was married, and he didn't want that. Thankfully, Mushu's lesson is mostly learned (he still makes the ancestors cater to his whims, but not only did they essentially kick-start the plot, they still treat Mushu like dirt even post-redemption, so they kinda had it coming).
In Cinderella III: A Twist in Time, Lady Tremaine. She was already a jerkass, but now she goes from abusing her stepdaughter to trying to kill her. Inverted with Anastasia, who becomes sympathetic and eventually makes a Heel–Face Turn.
The provider of the image in the trope's main page is the Once-ler from the 2012 adaptation of The Lorax, who undergoes a jarring change in temperament (as part of a Face–Heel Turn in a Descent into Darkness Song) when his Thneed business becomes a success, turning from a mostly good-natured guy into a greedy, arrogant Corrupt Corporate Executive, carelessly abusing and exploiting the forest creatures he'd previously befriended.
The whole town after they run out of Krabby Patties in The Sponge Bob Movie Sponge Out Of Water. They don't hesitate to kill SpongeBob after he offers himself as a sacrifice to the "Sandwich Gods".
Hal from Megamind. While he had shades of selfishness from the start, he never had a malicious streak in him and at least tried to be sophisticated towards Roxanne. Once he is given powers, however, he becomes a full-on Psychopathic Manchild who thoroughly believes that Roxanne belongs to him. The kicker is when he tries to kill Roxanne just for not returning his feelings and saying that she broke his heart, even though it is clearly not the case.
Bo Peep's is a little downplayed in Toy Story 4. She was shown more aloof compared to her previous appearances. For example, she was against helping Woody in saving Forky from Gabby Gabby and suggests he "cut [his] losses and go home".
Poppy receives this treatment throughout the plot of Trolls World Tour. She spends most of the movie constantly ignoring her friends and not considering the consequences of her poor decisions.
In Casper's Haunted Christmas, the Ghostly Trio are far bigger jerks than they usually are. In the other films, they are shown as jerks with hearts of gold who do care about Casper deep down despite frequently being mean to him, and they are shown to have Pet the Dog moments. In this film, they outright laugh when Casper is told he may be banished to the Dark and taunt him about it, only growing concerned when they are told they would be banished there as well. They also try to ruin Christmas just for kicks.
In BIONICLE 2: Legends of Metru Nui, Matau's just into the whole hero deal for sheer excitement, meanwhile Onewa seems to take every opportunity to belittle his companions, especially their leader Vakama. In the following movie Web of Shadows, Onewa' is demoted to an even more minor extra, and Matau takes over his role of a Jerkass, putting such a stress on Vakama with his constant complaining that it leads him to do a Face–Heel Turn. Matau makes up for it in the end by realizing how mean he was and bringing Vakama back to their side.
Red is significantly more hot-headed and doesn't work well with anyone, despite being fairly down-to-Earth and kind in the first movie.
For some reason, Nicky Flippers went from a suave, patient, and friendly Reasonable Authority Figure in the first movie to being considerably more ill-tempered in the second movie.
Harry Osborn. Goes from a mostly nice guy in the first movie to lashing out at Peter in the second movie and acting like a douchebag for most of his scenes. In the third film, he gets better via a little Easy Amnesia, but then reverts to full blown Rival Turned Evil. In the end, he redeems himself, but Redemption Equals Death.
Mary Jane also becomes increasingly self-centered as the series progresses. She has No Sympathy for Peter despite all the problems he has, refuses to hear his side of the story as to why he missed her play, and then dumps her fiancée at the altar to get with Peter! In the third movie, she resents Spider-Man's popularity for saving people's lives and not having the time for her, but this time she at least recognizes this as a negative behavior, does feel bad about it and tries to do better... but life doesn't make it that easy for her.
Even Peter himself took a level in the third movie. He develops a little Acquired Situational Narcissism in the beginning, then got on a vengeance kick, and then he got the Venom symbiote. You know the rest.
Alan from The Hangover. Initially, he was a well-meaning idiot whose only deeds were caused out of ignorance than malice. In the later films, however, he begins to be very rude and condescending towards everyone. In the second film, he deliberately drugs the Wolfpack in order to incapacitate Teddy, and in the third film, he begins to have a real bitterness towards Stu. Fortunately, at the end of the third film, he drops his rudeness to start his life over.
On Chesil Beach: Up until his wedding night, Edward is shown to be a mostly sympathetic, easygoing character. When Florence tells him she is uncomfortable with sex, Edward unravels and unleashes his anger on her. Without talking things over with her first or trying to understand her discomfort, Edward promptly ends their marriage—something he comes to regret later in life.
Titanic (1997) has the obnoxious aristocrat Caledon "Cal" Hockley, who starts out as a pompous, misogynistic Jerkass. He soon graduates to smack his fiancee around, trying to frame Jack for burglary, and when things really start to go south, kidnapping and attempted murder. He survives the Titanic sinking, but it's later revealed that he committed suicide after losing his fortune in the 1929 Stockmarket Crash.
Ash of the Evil Dead series does this over time. In the first film he's basically a Final Guy, by the second he's a badass, and in the third he's a full blown Jerkass. It makes sense, though. After going through some horrific events, losing a limb, nearly losing his mind, and having everyone die on him, he gets sucked into a time period where its residents initially treat him like crap, make him a slave, and then try to kill him. It's probably safe to say it'd be more disturbing if he didn't have a huge chip on his shoulder by that point.
Abigail Chase from the National Treasure series seems to take one between the first and second movies. In the first movie, she starts out as a tad bitchy, but really not without reason given the crap she ends up in thanks to Ben. By the end of the movie, she's considerably nicer and has evolved into a proper Love Interest. When the second movie comes around, she's reverted to the beginning of the first movie and gone even further, being worse than she was then. She changed the alarm code in what is most likely Ben's house, and she's hostile around him even when he's trying to be nice. He also has to bribe her to get her to help him clear his family's name.
In Deep Rising, Simon Canton's plan at first was to destroy the ship as an insurance scam, but to make it so all of the passengers live. Later though, he uses the others as bait so he can escape himself, and tries to kill Trillian and steal Finnegan's boat. Fortunately though, he meets a Karmic Death in the end.
In Iron Man 2 Tony Stark allows the fame to get to his head again, and it screws him over worse than his playboy tendencies did in the first film. However, it's something of a ruse. The power source for his arc reactor is poisoning him, pretty much having months to live/find an alt power source. With Hammer trying to get his tech and all of this, he lashes out yet also does it in a matter so Pepper can run the company and make sure it remains right while goading his friend into taking the prototype armor to become War Machine. He doesn't fully recover after seeing the final message from his dad, getting some much needed faith and hope.
Loki in Thor: Tragic Villain and Woobie, Destroyer of Worlds. Loki in The Avengers: psychopath who enjoys ripping a guy's eye out, and directly or indirectly kills around 200 people (80 people in the first two days — according to Black Widow, including those who died in and after the explosion caused by the Tesseract, unknown number of S.H.I.E.L.D. agents during the attack on the Helicarrier, plus 74 causalities during the Battle of NY — according to General Ross's data◊ in Captain America: Civil War). He gets better later though.
Steve Rogers Captain America himself in Captain America: Civil War), albeit he does have mostly sympathetic reasons for it (the death of Peggy for one, Bucky being falsely accused for another). In the previous movies while Steve could be a stick in the mud he pretty much always had justified and selfless reasons to do so. In Civil War however, Cap’s morals lines are far blurrier as he has an unpleasantly tribal mindset, believing the Avengers should be able to fight crime any way they want since “the safest hands are their own” and he’s willing to let all his teammates get captured and arrested so he and Bucky can escape and even drop a jet bridge on a teenager (though a superpowered one). The epitome of this however is The Reveal that Steve knew damn well Hydra and more specifically Bucky while brainwashed had assassinated Howard and Maria Stark and just refused to tell Tony their only son for multiple years. Though Steve did it partly to protect Bucky, it’s hard to deny that the armoured backhand across the room Tony gives him at the news, wasn’t rather deserved in that instance.
Wanda Maximoff aka Scarlet Witch is by far the most extreme example of this, though it is ultimately justified and consistent given the Trauma Conga Line she goes through. While Wanda obviously wasn’t a saint when she was introduced in Avengers: Age of Ultron (being along with her brother a Hydra volunteer who aids Ultron), she still had some moral compass and balked at what Ultron was planning. She pulls a Heel–Face Turn to good and in her nextthreemovies is presented as Not Evil, Just Misunderstood with Vision bringing out the best in her. By Doctor Strange in the Multiverse of Madness however she’s a mass murdering Fallen Hero and Dark Messiah who simply doesn’t give a crap about anything except having her twin sons Billy and Tommy in her life again. In fairness, this Jumping Off the Slippery Slope was well in making considering she was forced to kill Vision to save the universe but her sacrifice amounted to nothing and she had to say goodbye to him again along with her sons in her TV series — before discovering her sons were alive and well in other universes thanks to the Darkhold (which corrupted her further). Wanda does have a Heel Realization at the very end at least, after seeing Billy and Tommy be terrified of what a monster she’s become.
RoboCop: The “Old Man” chairman and chief executive officer of OCP gets this hard compared to his first appearance and the follow up media. In the 1987 film he’s a Cool Old Guy who is far more moral than Dick Jones or Bob Morton and his plans to help the people of Detroit seem genuinely noble. He is explicitly disgusted and horrified with Jones over the ED-2O9 killing Kenny and being shown evidence that Jones had Morton killed. The Old Man also has a wholesome “Nice shooting son” moment with Murphy before the credits role. In Robocop 2 however the Old Man is unmistakably a Corrupt Corporate Executive who greens light the inhumane Robocop 2 project and at one point literally step over an innocent civilian’s dead body like it’s nothing. RoboCop: Rogue City goes the extra step further of having him be the Greater-Scope Villain who thanks to Brain Uploading to a robot body is actually the Final Boss of the game.
Halloween II (2009) had Loomis of all people go through this, having no problems with morality or ethics whatsoever when it came to writing a book that allowed him to profit off the tragedy of the previous film. Fans were not happy about this change.
In Scarface (1983), Tony Montana starts out the film as a crook, but it's not until he gains power that he allows himself to become a cocaine-addicted wreck. He constantly curses and acts like a cantankerous prick towards even his friends, and gets called out on it by almost everyone close to him.
John Rambo in his fourth movie - although he is still one of "the good guys" - he is portrayed as more rude and cynical than in the first three movies. Considering everything he's been through up 'til then, it's perfectly understandable that he'd be a left a little bitter.
Rambo: "You're not gonna change anything."
Michael: "It's thinking like that that keeps the world the way it is."
Rambo: "Fuck the world."
Step Up: Sean is a pretty Nice Guy in the fourth movie but has several irritable, victory-obsessed Control Freak moments in the fifth one (such as breaking ties with his old crew for sensibly giving up on an impossible and humiliating series of auditions and not even having the decency to ask them if they want to audition for The Vortex before putting together a new crew). Multiple people call him out on his newfound abrasiveness.
When Noni decides to end things with semi-boyfriend Kid Culprit in Beyond the Lights, he accepts it surprisingly well and they maintain their friendship...for about 20 minutes. Never indicated to be more than kind of annoying (with a side of insensitivity- he actually tries to sext Noni right after she attempts to commit suicide by jumping off her balcony!), Kid Culprit crosses the line into outright Jerkassery when he publicly humiliates and basically sexually assaults Noni on-stage during their performance at the BET awards. He then goes on to claim that HE dumped HER because he was cheating on her, and that she's a bitch and a freak (ON NATIONAL TV). His behavior is so over-the-top that By-the-Book Cop Kaz ends up punching his lights out. As if all that weren't bad enough already, he then CONTINUES to trash Noni via Twitter, claiming that everything about her, including her accent, is fake. Just wow.
When he is first introduced in the Jurassic Park series, Dr. Henry Wu, InGen's chief geneticist, is a decent if incautious person. The "decent" part is more present in the first novel than the first film, the former of which sees him actively helping to repair the damage to which he unwittingly contributed, but he a nice guy in both nonetheless. Come Jurassic World more than 20 years later, and Wu has become a much more bitter and cynical person, indifferent to the latest casualties of his new Indominus rex and countering the resulting What the Hell, Hero? reprimand from Simon Masrani by contending that everything unique and successful about the park is ultimately thanks to him. Jurassic World Dominion however reverts Wu back to his nicer self from the first movie with him being The Atoner for his crimes.
Terminator 2: Judgment Day does this to 'Sarah Connor, who went from the naive but sweet girl we saw in the first movie into a hardened gun-tolling woman with no time for bullshit. As soon as she learns that Miles Dyson was the creator of SkyNet, her first instinct is to travel to his house and kill him on the spot with his wife and son present and then later goes on a rant that sounds a lot like something a so-called feminist would say. In a deleted scene, she attempts to destroy the T-800's control chip while he was offline despite the fact that the T-800 was the only thing keeping her and John safe from the much deadlier T-1000. This all, however, comes from the fact that she was greatly traumatized from her experiences in the first movie, how she's carrying the weight and desperation from knowing what's going to happen while nobody believes her, and when the chips are down and she's staring at Miles up close down the sight of a handgun, she can't pull the trigger and collapses to the floor in a blubbering heap.
Foolproof: Rob goes from the Plucky Comic Relief of the trio to an aloof, dedicated criminal under Leo's tutelage, sabotaging the others' attempt to get out from under Leo's thumb and then trying to kill them.Subverted with the reveal that he's still working with Kevin and Sam and is just trying to earn Leo's trust for the Batman Gambit to bring him down.
Nurse Betty: Rosa starts out as a supportive friend to Betty, but gets a lot more sour and irritable with her after realizing that she Cannot Tell Fiction from Reality and observes Betty luck into a romance with the actor who she thinks is the character he plays. She's more exasperated than cruel or bitter, though, and softens up again in the last few scenes.
Sweet, Sweet Lonely Girl: Adele starts out as a sweet girl taking care of her aunt. When influenced by Beth though Adele's soon neglected her aunt to the point of her death from ineffective heart medication Adele bought instead at Beth's urging so she could pocket the money left over since it was a cheaper price.
It's a Wonderful Knife (2023): Winnie briefly goes from a Nice Girl into cussing at her family, depressed over her friend Cara's death and how they treat her/react to this. She's returned to her old self by the end of the movie.
◊ in Captain America: Civil War). He gets better later though.
