History WithGreatPowerComesGreatInsanity / Film

* In ''WesternAnimation/TurningRed'', [[spoiler:Ming's kaiju-sized red panda spirit is quite feral and uncontrollable when angered, blindly destroying a concert with no concern for collateral damage. In fact, one of the main reasons why the other Lees urge caution to Mei about bonding with her panda spirit (if it's manageable enough) because ''some'' red panda spirits like Ming's are too destructive and ''have'' to be [[SupernaturalSealing sealed away]]. It's a SelfFulfillingProphecy due to generational habits, because in peacetime the descendants of Sun Yee regard the Blessing of the Gods as a burden, instead of the divine intervention it was always meant to be. Consequently, by rejecting the red panda, they and Ming are denying a fundamental part of themselves. By suppressing it, the spirit [[AnAesop can only come out explosively]] when it inevitably resurfaces. Happily, Ming gets better by the ending, treating her red panda as a family pet instead of a demonic entity.]]

** Doctor Octopus in ''Film/SpiderMan2'' is made crazy by his robot arms. In fact, they slaughter a room full of medical personnel while Otto is still unconscious. He overcomes their programming just in time for a HeroicSacrifice.

* Subverted in ''Film/AmazonWomenOnTheMoon,'' when Ed Begley, Jr. plays the son of the original invisible man. He creates a potion that he believes will turn him invisible but not insane. Unfortunately, he becomes insane but visible.

* ''Film/TheFly1986'' besides the eventually sickening BodyHorror, the worst part about Seth’s SlowTransformation is that the new state of being Seth accidentally brings upon himself drastically alters his personality and makes him go insane. It’s especially notable earlier on when Seth has been invigorated by his new strength and confidence, goes from a introverted but beautifully sweet NiceGuy to a deranged, aggressive, lustful, chauvinistic {{Jerkass}}. Several reviewers of the film, such as Ryan Hollinger note this psychological change is Seth in many ways more frightening and upsetting than the monster he becomes, as it suggest Seth always had the potential to be like this.
* ''Film/ForbiddenPlanet'' exhibits this principle most chillingly through Morbius. That is more of an EnemyWithout, though; Morbius seemed sane right up to the end. Morbius may have a mental block preventing him from understanding what has happened, because it was simply too horrible for him to accept that the monster is an inherent part of himself, which meant he had killed all of his friends.
* The villain in ''Film/{{Frostbite}}'' stated that his first goal was to ''cure'' vampirism, until he decided that he should ''enhance'' it instead.
* ''Film/HollowMan'', starring Creator/KevinBacon.

** As expected, the failure with Caine doesn't stop the government. In the sequel, they use the serum on several more people, including a decorated soldier (Creator/ChristianSlater), who also goes insane and starts killing people. Unfortunately, his soldier training makes him doubly difficult to kill. Unlike the scientist, who already had quite an ego, the soldier goes insane from a side effect of turning cells transparent. Since the skin no longer protects the brain from solar radiation, this causes unavoidable mutations and, as a result, insanity.
* Averted in ''Film/{{Lucy}}''. The title character stays rational, cool, and focused (perhaps getting even more so) as her power grows to godlike levels.

* Franchise/MarvelCinematicUniverse:
** Mechanical example with Obadiah Stane from ''Film/IronMan1''. While Obadiah was already an immoral ArmsDealer, upon donning a PoweredArmour suit of his own, he goes completely off his rocker, murdering and attacking people, including civilians, during his fight with Tony Stark. A stark contrast to the mature and sane businessman he was at the start of the film and quite different to Tony’s heroism when donning his suits.
** ''Film/{{The Incredible Hulk|2008}}'': The movie finds hardened veteran soldier Emil Blonsky being given [[PsychoSerum a prototype super-soldier serum]] -- to put "what I know now into the body of a man ten years younger". The combination of being defeated despite this and the taste of such power grows into the classic Comes Great Insanity. Funnily enough, that serum is all but directly stated to be the one that gave ComicBook/CaptainAmerica his powers, but with Blonsky lacking the additional radiotherapy, his insanity is a classic symptom of the SuperSoldier serum gone wrong. Then he demands (against repeated warnings) a dose of an even ''more'' experimental serum from a much ''less'' reputable source and... let's just say the end results of that little cocktail ain't pretty.
** Loki in both ''Film/{{Thor}}'' and ''Film/{{The Avengers|2012}}'' has his already troubled and insecure personality take a psychotic turn upon gaining power such as taking the Throne of Asgard in ''Thor'' and gaining a mind-control sceptre and army from Thanos in ''Film/TheAvengers2012''. Complicating matters further in the latter example is that the Mind Stone is part of sceptre and is implied to be affecting Loki’s already highly volatile mental state. Funnily enough, while not wielding great power, Loki is more sane and affable.
** In ''Film/CaptainAmericaTheFirstAvenger'', it's stated that [[Comicbook/RedSkull Johann Schmidt]] was the first person to receive the super-soldier serum, but for various reasons, namely a combination of the serum not being perfected yet as well as his dark inner nature, he received a tremendous power boost at the cost of his sanity (and his human form). Steve Rogers, however, is selected for being an IdealHero, and thus will be responsible with his power.
** With the exception of Pepper Potts, in ''Film/IronMan3'' everyone who gets injected with Extremis becomes incredibly unstable both [[SuperPowerMeltdown physically]] and mentally. Aldrich Killian, Eric Savin and Ellen Brandt display psychotic behaviour thanks to the newfound power, although in Aldrich’s case it helps he wasn’t the picture of good mental health to begin with.
** Zigzagged with Wanda Maximoff who jumped off the deep end once unlocking her powers due to a traumatic past, much like in the comics. In ''Film/AvengersAgeOfUltron'', her most psychotic and cruel moments are when using her powers to MindRape others, though she ultimately does a HeelFaceTurn and begins use her powers for good. [[spoiler: Played straight in ''Series/WandaVision'' where unable to cope with losing Vision after the events of ''Infinity War'', Wanda unwittingly unleashed her buried Chaos Magic to enslaves Westview and its inhabitants to her will and create a idyllic sitcom world for herself, viciously lashing out whenever someone tries to force her to accept the truth. In the end though, she finally realizes how much pain she's causing and accepts this is far from the healthiest way to process her grief, letting Westview go. Played straight again in ''Film/DoctorStrangeInTheMultiverseofMadness'' when Wanda becomes so consumed by the power of the Darkhold that her SanitySlippage is to the extent that she is unwilling to accept that her children were constructs created with her magic and starts JumpingOffTheSlipperySlope in her quest to find them by [[WouldHurtAChild trying to kill a child for her powers]], brutally kills anyone who tries to stop her, and nearly destroys the multiverse with her powers. Once again, she has a HeelRealization after seeing her sons terrified of her and [[RedemptionEqualsDeath redeems herself by destroying the Darkhold, seemingly dying in the process.]]]]
** Darren Cross from ''Film/AntMan1'' JumpsOffTheSlipperySlope in the climax when his schemes are foiled and he puts on the Yellowjacket shrinking suit, which he uses to capture Scott’s daughter Cassie so he can lure in and kill Scott. It is noted though that long before then, Darren was mentally unbalanced due to combination of experimenting with shrinking particles and [[WellDoneSonGuy desperately trying to impress his father figure Hank Pym]], who upon seeing Darren’s growing obsession, spurned him - which only set Darren off further. Lampshaded by Hank at one point in the film.
-->'''Hank Pym''': The process is highly volatile. If one isn't protected by a specialized helmet, it can affect the brain's chemistry. I don't think Darren realizes this, and, you know, he's not the most stable guy to begin with.
** Erik Killmonger from ''Film/{{Black Panther|2018}}'' was already a ruthless and cruel man but upon ingesting the Heart-Shaped Herb, which grants him the enhanced abilities of the Black Panther, he truly becomes an insane tyrant. His first action is to give the Elder who fed him the Herb a NeckLift while demanding that she burn the remaining plants. While fighting the Dora Milaje in the climax, Erik sports a massive SlasherSmile.
** Thanos from ''Film/AvengersInfinityWar'' and ''Film/AvengersEndgame'' is a complicated case. He was already a bit of head-case with a chip on his shoulder due to the [[LastOfHisKind extinction of his race]] on top of being a ruthless BloodKnight. But when donning the Infinity Gauntlet, he well and truly lived up to his moniker of "The Mad Titan" as he kills half of all life in the universe in ill-thought out plan to solve overpopulation. In ''Endgame'', he only gets worse as when the Avengers attempt to undo his actions, he decides to commit genocide on the ''entire universe'' and create a new, "grateful" one [[InTheirOwnImage in his own image]].
** Another mechanical example with Mysterio from ''Film/SpiderManFarFromHome''. BeneathTheMask Quentin Beck (which likely isn’t his real name) was initially just a {{jerkass}} with a petty grudge, but upon getting access to E.D.I.T.H and an army of Stark drones, he starts threatening to kill his colleagues for a slip up and attempts to murder a bunch of teenagers for sake of keeping his true identity a secret from the world.
* ''Film/TheMask'': Happens to Stanley Ipkiss whenever he wears the Mask (and when Milo puts it on as well). Dorian Tyrell, not so much. As explained above, the Mask unlocks the suppressed part of a person's psyche. Tyrell, an unrepentant criminal, already had all his nastiness full on the surface, so the Mask just made him invincible and monstrous.
* Agent Smith in ''Film/TheMatrixRevolutions''. Smith was already a sociopathic, short tempered and humanly volatile AI program in ''Film/TheMatrix'' but thanks to becoming an all powerful virus and absorbing the Oracle, he completely disregards any cold sensibility he once had letting loose a LargeHam EvilLaugh signify how insane he has become.

** In ''Film/SpiderMan1'', this is the origin of the Green Goblin. The process to make him a super soldier also seems to produce a homicidal second personality. Ironically, Norman [[WhatCouldPossiblyGoWrong subjected himself to the serum]] in an effort to prove it would ''not'' have that effect on humans...
** ComicBook/DoctorOctopus in [[Film/SpiderMan2 the second film]] was made crazy by the robot arms. In fact, they slaughtered a room full of medical personnel while Otto was still unconscious. He overcame their programming just in time for a HeroicSacrifice.
** Same with Flint Marko in [[Film/SpiderMan3 the third]]. He wasn't an especially good person before the accident that turned him into Sandman, but afterward he was just nuts. Eddie Brock, on the other hand, started out as a psycho; gaining the Venom symbiote just allowed him to express it in new ways. Flint Marko was ''desperate'', which led to all the bad things he was involved in (including his part in Ben's murder). He needed money desperately to save his daughter's life, and would do anything to get it.

** A CentralTheme with the Force is that the more in-tune the wielder is, the greater risk of the person being insanely DrunkWithPower and turning to TheDarkSide. Most Sith Lords and Dark Jedi seen in the franchise are either unhinged and volatile at best and AxCrazy and cackling at worst. Even the more aloof Darth Maul and Count Dooku display psychotic tendencies, which is likely due to the Dark Side feeding off negative emotions.
** Anakin Skywalker, aside from being a case of FromNobodyToNightmare fell to this. As he grew from [[Film/ThePhantomMenace a rescued slave]] turned Jedi Padawan to Jedi Knight proper steadily becoming stronger and stronger, Anakin’s mental stability began to deteriorate in direct correlation to his rise in Force power. Further triggered by [[Film/AttackOfTheClones the torture and the murder of his mother]] and [[Film/RevengeOfTheSith visions of his wife Padme dying]], Annie soon became convinced he could become the most powerful Jedi ever in order to prevent his loved ones’s deaths and fall under the influence of BigBad Palpatine. After killing Mace Windu Anakin JumpedOffTheSlipperySlope and became psychotic murdering Sith Lord who willingly Force choke even his pregnant wife. Ironically as [[Film/ANewHope Darth Vader]] he isn’t as AxCrazy, but still opts to strangle people on a whim and frequently shows his unstable side in expanded material.
** [[Film/TheForceAwakens Ben Solo]], Anakin’s grandson similarly displays an extremely volatile mental state which seems to suggest it may be InTheBlood. Despite having loving parents and a CoolUncle Ben, due to almost getting killed by a droid as a toddler, growing up isolated and having daunting expectations put upon him - all made him quite unbalanced like Anakin. This became worse when Ben developed his Force powers as thanks to his mighty heritage he excelled at his training whilst simultaneously becoming more obsessed with power and proving himself to others. This made Ben a easy target for Snoke [[spoiler: a puppet of Palpatine]] who turned Ben to the dark side and help him become Kylo Ren a psychotic dark Force-user like his grandfather before him.
** Sheev Palpatine is a much less complicated case, but still a prime example of this. Already an arrogant and immoral RoyalBrat from Naboo, he already had the makings of an EnfantTerrible long before sensing Darth Plageis through the Force and meeting with him. Upon becoming a powerful Sith Lord, Palpatine’s unstable qualities skyrocketed and after killing his master and infiltrating the Senate he became the cackling AxCrazy PersonOfMassDestruction we know today.

%%* ''Film/UniversalSoldier''. In the sequel, one of them even gets an artificially intelligent, ''Self-Evolving Thought Helix'' military supercomputer downloaded into them.
* In ''Film/TheWolfMan2010'', [[spoiler:Sir John's lycanthropy has most certainly gone to his head]].
* Jean Grey in her manifestation as Dark Phoenix in ''Film/XMenTheLastStand''. Although it is explained that she was already mentally unstable as a girl and her massive powers had to be reduced for her own good and that of everyone around her by putting mental blocks into her psyche. When these were removed, she started killing people with her mind. [[note]](This is actually closer to the original Phoenix story than the later comic and adaptation stories that portray Jean as having been TouchedByVorlons; see the Comic Books section above.)[[/note]]

* In ''Film/RoboCop2'', the evil corporation OCP attempts to build a successor to [=RoboCop=], but in all cases the new cyborg goes crazy and commits suicide. Finally, they stick the brain of a convicted, drug-addicted, psychopath into the cyborg. That doesn't work out too well in the end, either. Ironically, the scientists theorize that [=RoboCop=] was a success due to the very qualities that made Murphy a good cop in life: his highly Catholic upbringing and stable family life imbued him with a strong moral compass, selfless devotion to duty, and an [[ICannotSelfTerminate aversion to suicide]]. Then they turn around and choose a murderous psychopath, because they thought that they could control him through his drug addiction. Umm... Nope. Their reasoning was that just as a selfless cop would not kill himself, a sociopath would desire the power and immortality that comes with being an indestructible cyborg. While this is true, [[IdiotBall nobody seemed to catch onto the fact that a RoboCop also needed to be dedicated to duty rather than, say, murdering everybody to get a fix]]. Not only would a sociopathic criminal not care about duty, they also didn't see fit to hardcode directives into it like they did with the original.

* In ''WesternAnimation/TurningRed'', Ming's kaiju-sized red panda spirit is quite feral and uncontrollable when angered, blindly destroying a concert with no concern for collateral damage. In fact, one of the main reasons why the other Lees urge caution to Mei about bonding with her panda spirit (if it's manageable enough) because ''some'' red panda spirits like Ming's are too destructive and ''have'' to be [[SupernaturalSealing sealed away]]. It's a SelfFulfillingProphecy due to generational habits, because in peacetime the descendants of Sun Yee regard the Blessing of the Gods as a burden, instead of the divine intervention it was always meant to be. Consequently, by rejecting the red panda, they and Ming are denying a fundamental part of themselves. By suppressing it, the spirit [[AnAesop can only come out explosively]] when it inevitably resurfaces. Happily, Ming gets better by the ending, treating her red panda as a family pet instead of a demonic entity.

** Thanos from ''Film/AvengersInfinityWar'' and ''Film/AvengersEndgame'' is a complicated case. He was already a bit of head-case with a chip on his shoulder due to the [[LastOfHisKind extinction of his race]] on top of being a ruthless BloodKnight. But when donning the Infinity Gauntlet, he well and truly lived up to his moniker of "The Mad Titan" as he kills half of all life in the universe in ill-thought out plan to solve overpopulation. In ''Endgame'', he only gets worse as when the Avengers attempt to undo his actions, he decides to commit genocide on the ''[[UpToEleven entire universe]]'' and create a new, "grateful" one [[InTheirOwnImage in his own image]].

** Mechanical example with Obadiah Stane from ''Film/IronMan1''. While Obadiah was already immoral, upon donning PoweredArmour suit of his own he goes completely off his rocker, murdering and attacking people including civilians during his fight with Tony Stark. A stark contrast to mature and sane businessman he was at the start of the film and quite different to Tony’s heroic behaviour when donning his suits.
** ''Film/{{The Incredible Hulk|2008}}'': The movie finds hardened veteran soldier, Emil Blonsky, given [[PsychoSerum a prototype super-soldier serum]] -- to put "what I know now into the body of a man ten years younger". The combination of being defeated despite this and the taste of such power grow into the classic Comes Great Insanity. Funnily enough, that serum is all but directly stated to be the one that gave ComicBook/CaptainAmerica his powers, but with Blonsky lacking the additional radiotherapy, his insanity is a classic symptom of the SuperSoldier serum gone wrong. Then he demands (against repeated warnings) a dose of an even ''more'' experimental serum from a much ''less'' reputable source and... let's just say the end results of that little cocktail ain't pretty.
** Loki in both ''Film/{{Thor}}'' and ''Film/{{The Avengers|2012}}'' has his already troubled and insecure personality take a psychotic turn upon gaining power such as taking the Throne of Asgard in ''Thor'' and getting powerful sceptre and army from Thanos in ''The Avengers''. Conflicting matters further in the latter example is that the Mind Stone is part of sceptre and is implied to effecting Loki’s already highly volatile mental state. Funnily enough while not wielding great power, Loki is more sane and affable.
** In ''Film/CaptainAmericaTheFirstAvenger'', it's stated that [[Comicbook/RedSkull Johann Schmidt]] was the first person to receive the super-soldier serum, but for various reasons, namely a combination of the serum not being perfected yet as well as his dark inner nature, he received a tremendous power boost at the cost of his sanity (and his human form). Steve Rogers himself, however, is selected for being an IdealHero, and thus will be responsible with his power.

** Wanda Maximoff much like the comics jumped off the deep end once unlocking her powers. In ''Film/AvengersAgeOfUltron'' her most psychotic and cruel moments are when using her ability to MindRape others, she does HeelFaceTurn to heroism and use her powers for good though. [[spoiler: Played straight in ''Series/WandaVision'' as unable to cope with losing Vision after the events of ''Infinity War'', Wanda unleashed her buried Chaos Magic to enslaves Westview and its inhabitants to her will and create a idyllic world for herself and viciously lashes out whenever someone tries to force her to accept the truth. In the end though, she does accept this far from the healthiest way to process grief and lets Westview to go. Played straight again in ''Film/DoctorStrangeInTheMultiverseofMadness'' when Wanda becomes so consumed by the power of the Darkhold that ''her entire mental health'' deteroriates to the extent that she, unwilling to accept that her children are constructs she created with magic, starts JumpingOffTheSlipperySlope in her quest to find them by [[WouldHurtAChild trying to kill a child for her powers]], starts killing everyone else who tries to stop her, and nearly destroyed the multiverse with her powers. In the end, though, she [[RedemptionEqualsDeath redeems herself by destroying the Darkhold and seemingly dies.]]]]
** Darren Cross from ''Film/AntMan1'' JumpsOffTheSlipperySlope in the climax when his schemes are foiled and he puts on the Yellow Jacket shrinking suit which he uses to immediately try and kill Scott’s daughter Cassie. It is noted though long before then, Darren was mentally unbalanced due to combination of experimenting with shrinking particles and desperately trying to impress his father figure Hank Pym who seeing Darren’s growing obsession, spurned him - which only set Darren off further. Lampshaded by Hank at one point in the film.

** Erik Killmonger from ''Film/{{Black Panther|2018}}'' was already a ruthless and cruel man, but upon taking the Heart Shape Herb which gives him enhanced abilities he truly becomes an insane tyrant. His first actions are giving woman who feed him the Herb a NeckLift and while fighting Dora Milaje in the climax Erik has a massive crazy SlasherSmile on his face.
** Thanos from ''Film/AvengersInfinityWar'' and ''Film/AvengersEndgame'' is a complicated case, he was already a bit of head-case with a chip on his shoulder at extinction of his race on top of being ruthless BloodKnight. But when donning the Infinity Gauntlet, he well and truly lived up to his monicker of “The Mad Titan” as he kills half the life in the universe in ill-thought out plan to solve overpopulation. In ''Endgame'' he only gets worse as when his actions are undone, he decides he’s gonna commit genocide on everything and create a new “grateful” universe.
** Another mechanical example with Mysterio from ''Film/SpiderManFarFromHome''. BeneathTheMask Quentin Beck (which likely isn’t his real name) was initially just a {{jerkass}} with a petty grudge, but upon getting access to E.D.I.T.H and army of drones he starts threatening to kill his colleagues and attempts to murder a bunch of teenagers for sake of keeping his true identity a secret from the world.

** Wanda Maximoff much like the comics jumped off the deep end once unlocking her powers. In ''Film/AvengersAgeOfUltron'' her most psychotic and cruel moments are when using her ability to MindRape others, she does HeelFaceTurn to heroism and use her powers for good though. [[spoiler: Played straight in ''Series/WandaVision'' as unable to cope with losing Vision after the events of ''Infinity War'', Wanda unleashed her buried Chaos Magic to enslaves Westview and its inhabitants to her will and create a idyllic world for herself and viciously lashes out whenever someone tries to force her to accept the truth. In the end though, she does accept this far from the healthiest way to process grief and lets Westview to go.]]

** A CentralTheme with TheForce is that the more in tuned the wielder is, the greater risk of the person being insanely DrunkWithPower and turning to TheDarkSide. Most Sith Lords and Dark Jedi seen in the franchise are either unhinged and volatile at best and AxCrazy and cackling at worst. Even the more aloof Darth Maul and Count Dooku display psychotic tendencies, which is likely due to the Dark Side feeding off negative emotions.

** ''Film/TheIncredibleHulk'': The most recent movie finds hardened veteran soldier, Emil Blonsky, given [[PsychoSerum a prototype super-soldier serum]] -- to put "what I know now into the body of a man ten years younger". The combination of being defeated despite this and the taste of such power grow into the classic Comes Great Insanity. Funnily enough, that serum is all but directly stated to be the one that gave ComicBook/CaptainAmerica his powers, but with Blonsky lacking the additional radiotherapy, his insanity is a classic symptom of the SuperSoldier serum gone wrong. Then he demands (against repeated warnings) a dose of an even ''more'' experimental serum from a much ''less'' reputable source and... let's just say the end results of that little cocktail ain't pretty.
** Similar to ''[[VideoGame/FinalFantasyVI Kefka Palazzo]]'', it is hinted in ''Film/CaptainAmericaTheFirstAvenger'' that [[Comicbook/RedSkull Johann Schmidt]] was the first person to receive the supersoldier serum, but for various reasons, namely a combination of the serum not being perfected yet as well as his dark inner nature, he received a tremendous power boost at the cost of his sanity (and his human form). Steve Rogers himself, however, is selected for being an IdealHero, and thus will be responsible with his power.
** Mechanical example with Obadiah Stane from ''Film/IronMan''. While Obadiah was already immoral, upon donning PoweredArmour suit of his own he goes completely off his rocker, murdering and attacking people including civilians during his fight with Tony Stark. A stark contrast to mature and sane businessman he was at the start of the film and quite different to Tony’s heroic behaviour when donning his suits.
** Similarly Darren Cross from ''Film/AntMan'' JumpsOffTheSlipperySlope in the climax when his schemes are foiled and he puts on the Yellow Jacket shrinking suit which he uses to immediately try and kill Scott’s daughter Cassie. It is noted though long before then, Darren was mentally unbalanced due to combination of experimenting with shrinking particles and desperately trying to impress his father figure Hank Pym who seeing Darren’s growing obsession, spurned him - which only set Darren off further. Lampshaded by Hank at one point in the film.
-->'''Hank Pym''': The process is highly volatile. If one isn't protected by a specialized helmet, it can affect the brain's chemistry. I don't think Darren realizes this, and, you know, he's not the most stable guy to begin with.

** Loki in both ''Film/{{Thor}}'' and ''Film/TheAvengers2012'' has his already troubled and insecure personality take a psychotic turn upon gaining power such as taking the Throne of Asgard in ''Thor'' and getting powerful sceptre and army from Thanos in ''The Avengers''. Conflicting matters further in the latter example is that the Mind Stone is part of sceptre and is implied to effecting Loki’s already highly volatile mental state. Funnily enough while not wielding great power, Loki is more sane and affable.
** Erik Killmonger from ''Film/BlackPanther'' was already a ruthless and cruel man, but upon taking the Heart Shape Herb which gives him enhanced abilities he truly becomes an insane tyrant. His first actions are giving woman who feed him the Herb a NeckLift and while fighting Dora Milaje in the climax Erik has a massive crazy SlasherSmile on his face.
** Another mechanical example with Mysterio from ''Film/SpiderManFarFromHome''. BeneathTheMask Quentin Beck (which likely isn’t his real name) was initially just a {{jerkass}} with a petty grudge, but upon getting access to E.D.I.T.H and army of drones he starts threatening to kill his colleagues and attempts to murder a bunch of teenagers for sake of keeping his true identity a secret from the world.
** Thanos from ''Film/AvengersInfinityWar'' and ''Film/AvengersEndgame'' is a complicated case, he was already a bit of head-case with a chip on his shoulder at extinction of his race on top of being ruthless BloodKnight. But when donning the Infinity Gauntlet, he well and truly lived up to his monicker of “The Mad Titan” as he kills half the life in the universe in ill-thought out plan to solve overpopulation. In ''Endgame'' he only gets worse as when his actions are undone, he decides he’s gonna commit genocide on everything and create a new “grateful” universe.

** Wanda Maximoff much like the comics jumped off the deep end once unlocking her powers. In ''Film/AvengersAgeOfUltron'' her most psychotic and cruel moments are when using her ability to MindRape others, she HeelFaceTurn to good and use her powers for good though. [[spoiler: Played straight in Series/WandaVision as unable to cope with losing Vision after the events of ''Infinity War'', Wanda unleashed her buried Chaos Magic to enslaves Westview and its inhabitants to her will and create a idyllic world for herself and viciously lashes out whenever someone tries to force her to accept the truth. In the end though, she does accept this far from the healthiest way to process grief and lets Westview to go.]]

** ''Film/TheIncredibleHulk'': The most recent movie finds hardened veteran soldier, Emil Blonsky, given [[PsychoSerum a prototype super-soldier serum]] -- to put "what I know now into the body of a man ten years younger". The combination of being defeated despite this and the taste of such power grow into the classic Comes Great Insanity. Funnily enough, that serum is all but directly stated to be the one that gave ComicBook/CaptainAmerica his powers, but with Blonsky lacking the additional radiotherapy, his insanity is a classic symptom of the SuperSoldier serum gone wrong. Then he demands ([[WhatAnIdiot against repeated warnings]]) a dose of an even ''more'' experimental serum from a much ''less'' reputable source and... let's just say the end results of that little cocktail ain't pretty.

* Film/BackToTheFuturePartII: Biff was already a snide BadBoss to George in the original timeline. But after his future self goes back in time and helps his younger self make a fortune through sports betting, BadFuture Biff becomes a monstrously corrupt CorruptCorporateExecutive thanks to his newfound wealth and power, murdering George and getting away with it, and happily mistreating Lorraine and Marty to his hearts' content.