Not all movie maniacs are like the Joker – that is, crazy from the get-go. When the Taylors hire a surrogate in 'When the Bough Breaks' (in theaters Sept. 9), they're just excited for the new baby. That is, until things take a weird turn for the nightmarish. Read on for more villains who didn't start off being the worst--they just ended up that way. 

Jake Gyllenhaal in 'Nightcrawler'

Lou Bloom (Jake Gyllenhaal) in 'Nightcrawler’ is just your standard-issue oddball whose need to make a buck dovetails with his obsession with crime. Not so good when you start creating the crime yourself.

William “D-Fens” Foster in 'Falling Down'  

Michael Douglas’ nerdy defense engineer, recently laid off and divorced, takes his frustrations out on the entire city of Los Angeles. Released less than a year after the L.A. riots, ‘Falling Down’ captures the tense mood of the city at the time.

Travis Bickle in 'Taxi Driver' 

Robert De Niro has played a score of unstable characters, but none are as iconic as Travis Bickle -- a Vietnam vet whose loneliness and depression get the best of him. Please note: A person sporting a mohawk isn’t always a deranged vigilante.

Erica Bain in 'The Brave One'  

Who says only men can go berserk? Jodie Foster, herself a 'Taxi Driver' alumna, plays a radio personality who, in desperation, acquires a gun after a tragic mugging. Like Travis Bickle and D-Fens, she soon loses herself to vigilantism.

Clyde Shelton in 'Law Abiding Citizen'  

Shelton (Gerard Butler) swears revenge on the thugs who murdered his wife and daughter, which is understandable. But this ex-CIA assassin takes it too far, and it’s clear to Jamie Foxx that the grieving family man has gone off the deep end.

Private Pyle in 'Full Metal Jacket'  

War is hell. But sometimes boot camp can be even worse. Ask Private Leonard Lawrence (Vincent D’Onofrio), aka “Private Pyle,” who, shall we say, doesn’t respond well to his drill sergeant’s (R. Lee Ermey) constant badgering.

Jack Torrance in 'The Shining'  

Speaking of Stanley Kubrick films, you can't overlook the man with a terrifying case of writer’s block who starts off a family guy, ends up a raving lunatic bent on killing said family. (We do love that Jack Nicholson’s take on Jack Torrance seems a bit nutty from the start.)

Nina Sayers in 'Black Swan' 

Perfection is key in ballet, so it’s no surprise that ballerinas deal with an inordinate amount of stress. But “stress” doesn’t even begin to describe what this paranoid dancer (Natalie Portman) experiences as she rehearses for ‘Swan Lake.’

Leonard Shelby in 'Memento'  

Once upon a time, movies romanticized amnesiacs. This is not the case with Leonard (Guy Pearce), the vindictive widower whose short-term memory loss doesn’t stop him from ultimately becoming the villain of his own story.

Harvey Dent in 'The Dark Knight'  

Christopher Nolan, who also made ‘Memento,’ clearly has an affinity for tragically cracked characters. Exhibit A: Gotham City’s upstanding D.A. (Aaron Eckhart), who turns to the dark side -- and becomes Two-Face -- after his girlfriend’s death and his own disfigurement. 

Jean Grey in 'X-Men: The Last Stand'  

A flirtation with evil is nothing new for superheroes. The “Dark Phoenix” saga remains a milestone in the X-Men comics, and it’s brought to life in this sequel as Jean Grey (Famke Janssen) succumbs to her runaway telekinetic powers.

Max Dillon/Electro in 'The Amazing Spider-Man 2' 

Let’s not forget this comic book trope: almost every supervillain starts off fairly decent, if a little odd. Take, for example, this geeky engineer (Jamie Foxx) who idolizes Spider-Man – until a swim with some electric eels changes his attitude.

Max Rockatansky in 'Mad Max'  

They don’t call him “mad” for nothing. In the role that made him a star, Mel Gibson plays a decent cop who concocts some indecent methods of revenge after – you guessed it – his wife and child are killed by thugs.