Hollywood is a dream machine, but dreams take a lot of work. A shocking number of iconic cinematic works have only happened because some weird accident forced filmmakers to adapt. But the soul of artistry is improvisation, which is how these movies became classics.
Jaws: Al Pacino Sprains His Ankle
In 1975, Al Pacino was building some serious career heat. After the double-whammy of “Godfather” and “Godfather Part II,” he was cast as the lead of a film from an up and coming director named Steven Spielberg. But an ankle injury while chasing a rabbit on set forced them to recast, and the title role in “Jaws” ended up going to a mechanical shark named Bruce. History made!
Trainspotting: The Discovery of Opium in 3400 BCE
Way back in the third millennium BCE, an Egyptian farmer named Iry-Hor accidentally scorched some oozing resin from one of the poppy plants he cultivated and got super high. Thousands of years later, boom! Danny Boyle’s heroin chic flick “Trainspotting” is a hit.
Teen Wolf: Michael J. Fox Got Bit 
Here’s a wild one: on the set of 1985’s “Teen Wolf,” star Michael J. Fox actually got bit and transformed into a monstrous creature! To be fair, he was bit by a radioactive spider and empowered with the proportional strength of an arachnid, rather than a wolf. The abilities he gained powered him through the grueling shooting schedules of both “Teen Wolf” and “Family Ties,” and helped defeat The Kingpin.
Ascenseur pour l’échafaud: The Cast Thought They Were Supposed to Speak French
This 1963 crime thriller, also known as “Elevator to the Gallows,” was set to begin filming when a script supervisor realized that the cast had accidentally been given French versions of the script. Despite Jeanne Moreau and Maurice Ronet only being able to deliver dialogue phonetically, everyone rolled with it. A New Wave classic was born!
A Better Tomorrow: Chow Yun-Fat Sets His Allowance on Fire
Hong Kong director John Woo was in the habit of keeping one camera rolling at all times on set, and good thing! Otherwise, he never would have caught the moment star Chow Yun-Fat accidentally got his weekly allowance from his parents too close to a lit candle. The following moments of Yun-Fat frantically stamping out the flames and bemoaning that he didn’t get his next allowance till Monday was cut, although it can be found in the 2003 DVD Deleted Scenes.
Casablanca: Some Nazis Wandered on Set
Perhaps the greatest romance in all of cinema, Casablanca was filmed while World War II was still ongoing. So when some Nazi officers wandered onto set while looking for state secrets, director Michael Curtiz simply incorporated them into the plot. Guerilla filmmaking at its finest.
The Matrix: The Wachowskis Got Too Close to The Truth
Remember, it’s a fictional movie. Whatever the Wachowskis stumbled across while filming, it’s just a movie. Watch passively and conserve your energy.
The Godfather: Marlon Brando Showed Up to Set Relatively Prepared
Francis Ford Coppola knew Marlon Brando’s chaotic reputation before filming and was prepared for anything. But nothing could have prepared the crew of “The Godfather” for Brando showing up in shape, cheerfully sitting in the makeup chair and knowing a lot of his lines! That’s the kind of happy accident that makes a classic.
Reservoir Dogs: Missing Dogs
Quentin Tarantino loves telling stories, especially the one about how the original cast of “Reservoir Dogs” got loose while lighting was being set. After Los Angeles County Animal Control demanded feature player roles for their dogcatchers, the resourceful first-time director simply cast Steve Buscemi, Harvey Keitel and a Doberman named Mr. Blonde. The perfect cast.
The Piano: Harvey Keitel Kept Losing His Pants
And speaking of Keitel! Jane Campion’s period drama “The Piano” won three Oscars in 1994, but what critics didn’t know was that much of the erotic tension of the film was written on the fly after Keitel couldn’t seem to hang on to his pants for more than 90 minutes at a time. The movie was originally about a talking piano who saves Christmas.
Raiders of the Lost Ark: They Lost the Ark
Whoops! Apparently, George Lucas absent-mindedly parked his Toyota over the Ark and it wasn’t discovered until shooting was nearly over. By that time, Spielberg had utilized his technique of “not showing the shark or the ark” to build tension. Also, it’s a better title than the original Indiana Jones and the Ark That’s Right Over There.
Lawrence of Arabia: Casting of Peter O’Toole
In one of the biggest snafus in casting history, some doofus accidentally cast Peter O’Toole to be out in the desert! That guy got hella sunburnt, but it also cemented the storyline of the white savior in Hollywood imagination. Classic!