These days, filmmakers and producers have trained us to keep a watchful eye out for easter eggs—little jokes and references snuck into the film that otherwise serve no other purpose than a winking, "See what we did there?" And while we collectively gab about these sneaky surprises like well-informed cinephiles, the truth is that your favorite movie is likely hiding a far deeper trove of secrets.

For instance: did you know that one of the greatest Pixar films was almost deleted? Or that the biggest movie of 1976 was written entirely, first draft to last, in two weeks? Or that one of cinema's most legendary lines was improvised? Herein, we reveal the truth behind these (and more!) silver-screen secrets. Read on for the best movie facts and prepare to clean house at the next Hollywood trivia night. And for more wild facts out of Hollywood, learn the 50 Crazy Celebrity Facts You Won't Believe Are True.

1 James Cameron Drew That Charcoal of Naked Kate Winslet

That slightly scandalous charcoal drawing of a topless Kate Winslet in Titanic was drawn by none other than the director himself, James Cameron. If you want something done right, sometimes you just need to do it yourself. And for more trivia from this seminal film, check out the 20 Facts That Titanic Gets Wrong.

2 Alien's Androids Are Alphabetized

While the Alien franchise swaps in different androids for (almost) every installment, there is an interesting consistency to them: they go in alphabetical order. Ash, Bishop, Call, and, most recently, David (played by Michael Fassbender in Prometheus and Alien: Covenant).

3 There Will Be Blood Disrupted Shooting for No Country for Old Men

The two instant-classic pseudo-westerns of 2007 filmed in the same area of Marfa, Texas, around the same time, which created issues when a pyrotechnical test for There Will Be Blood created a huge smoke cloud that got into the shot for No Country For Old Men. Joel and Ethan Coen had to wait for it to dissipate before they could get back to shooting.

Image via Wikimedia Commons

4 Psycho Is the First U.S. Film to Feature a Toilet Flushing

At a time it was considered inappropriate to show a toilet being flushed on screen, Alfred Hitchcock saw an opportunity to add some extra shock to his already shocking film—presenting a scrap of paper, which proves an important clue, failing to flush in a toilet. In the book, the clue was an earring found in the bathroom, but Hitchcock changed it to a piece of paper actually in the toilet, partly to add an extra jolt for viewers. And for more wacky info from Hollywood, don't miss the 20 Craziest Celebrity Rumors of All Time.

5 Toy Story 2 Was Almost Deleted

A command entered in the "master machine" where the animation for Toy Story 2 was stored deleted 90 percent of the work the Pixar team had done on it. As Mental Floss describes, "A plan was quickly hatched to restore the data from a regular backup, which meant that only half a day of work would have been lost. But the backup system had failed. Pixar, incredibly, did not have a copy of the Toy Story 2 files on its servers." Fortunately, the film's technical director had a copy she had been working on from home, and much of it was restored.

6 Pet Rats Sold Big After Ratatouille

After the success of the 2007 film telling the story of the lovable, culinary-inspired vermin, kids everywhere asked their parents, "Can we get one? I promise I'll take care of it." At least one domestic pet chain saw sales of pet rats jump 50 percent after the movie's release. We wonder how many of those rats immediately became parental responsibilities…

7 And Clownfish Vanished After Finding Nemo

Just as there was a run on pet rats, the population of clownfish in their natural habitats took a precipitous drop following the release of Finding Nemo, which stars a clownfish. Marine biologists reported that the numbers of the fish dropped by as much as 75 percent in the Australian reefs they inhabit.

8 The Wallet in Pulp Fiction Was Quentin Tarantino's

Jules' wallet in Pulp Fiction that reads "Bad #&$&*@$" actually belonged to the director—who picked it up because of its reference to the 1971 film Shaft. As it happened, Samuel L. Jackson would go on to play the character that inspired the wallet in the 2000 remake of Shaft.

9 Casablanca's Sam Was a Drummer

Though now famous as the piano player at Rick's Café Américain, Dooley Wilson, the actor who played Sam, was an experienced musician and bandleader—but not a piano player. He was a drummer, and mimed the piano playing. "As Time Goes By" was dubbed in later.

10 Paul Schrader Wrote Taxi Driver in Two Weeks

Though it would quickly cruise its way into film history, the script for Taxi Driver came together in just a few days. As screenwriter Paul Schrader told The Hollywood Reporter, "I crashed at an ex-girlfriend's place, and I just wrote continuously. The first draft was maybe 60 pages, and I started the next draft immediately, and it took less than two weeks."

10 The Snow in Wizard of Oz Is Asbestos

In that famous poppy-field scene in Wizard of Oz, the snow coming down is calming to Dorothy and her posse. But they should probably have been far less relaxed as these were actually asbestos-based fake snowflakes—a popular Christmas decoration throughout the United States and Europe at the time. Wicked, indeed.

12 There Were 10,297 Balloons in Up

The animators who created the pack of balloons in Up actually created every single one. The film's effects artist, Jon Reisch, told Tech Radar that, "The entire canopy is filled with balloons. We didn't just simulate the outer shell." And they even got a specific count of exactly the number of balloons: 10,297.

13 Jurassic Park Raptors Sound Like Tortoises Mating

The terrifying noises made by the raptors in Jurassic Park were sourced from recordings of tortoises mating. The sound designer also experimented with horses breathing and geese hissing, but the tortoises proved the most evocative.

14 Toto Earned More Than the Munchkins on The Wizard of Oz

A lot more, in fact. The canine actor earned $125 per week for his efforts, while the actors playing the Munchkins brought in just $50 a week.

15 Jaws' Most Famous Line Was Improvised

The best-known line from Jaws ("You're gonna need a bigger boat," not "We're gonna need a bigger boat," as it's often misquoted, by the way) was not in the actual script. Actor Roy Scheider said it throughout the filming, joking about the small boat the producers had selected to hold the filming equipment, and it ended up in the final cut.

16 Three Major Horror Franchises Were Inspired by the Same Serial Killer

It takes one particularly terrifying creep to inspire Hannibal Lecter, Norman Bates, and Leatherface, but that's the legacy left by horrifying serial killer Ed Gein. When he was finally caught and his house of horrors in Plainfield, Wisconsin, discovered, police found masks and lampshades made from human skin, among plenty of other atrocities. His astonishing depravity proved a source of creative inspiration.

Image via Wikimedia Commons

17 Gene Hackman Was Originally Going to Play Hannibal Lecter

Speaking of Hannibal the cannibal, while Anthony Hopkins turned the crazy-smart serial killer into an unforgettable cultural touchstone, the role was originally supposed to go to Gene Hackman, who bought the rights to The Silence of the Lambs and had planned on directing the film himself. He backed off the project when he decided that the role was too dark for his taste.

18 The Most Profitable Film of All Time Is Paranormal Activity

Thanks to its microscopic budget and major success at the box office, the 2007 film Paranormal Activity, scored a return on investment of 19,758 percent, absolutely blowing away the next most profitable film (2015 horror film The Gallows, with an ROI of 6,843 percent). It cost just $60,000 to make and another $400,000 or so to market, yet ultimately brought in more than $89 million.

19 The Two Least Profitable Films Both Take Place on Mars

If you're looking to score big box office bucks, stay away from Mars. The two biggest money losers of all time both take place on that planet, with the 2012 sci-fi bomb John Carter holding the No. 2 spot with a loss of almost $127 million, outdone only by Mars Needs Moms, from a year earlier, which lost its studio more than $143 million—the worst ROI ever.

20 Butch Cassidy and the Sundance Kid Was Originally the Other Way Around

The original script for Butch Cassidy and the Sundance Kid, by William Goldman, was originally titled The Sundance Kid and Butch Cassidy. That all flipped when Paul Newman, maybe the biggest star on the planet at the time of production, took the role of Butch.

21 Harry Potter Has Brit Rock Cameos

The Harry Potter franchise boasts basically every British character actor in film, but it also squeezed in some British rock stars, too. In Harry Potter and the Goblet of Fire, The Weird Sisters include Pulp members Jarvis Cocker and Steve Mackey as well as Radiohead's Jonny Greenwood and Phil Selway.

22 American Psycho Was Inspired by Tom Cruise

Christian Bale explained that he drew inspiration from a Cruise interview on David Letterman's show, in which he was struck by the star's "very intense friendliness with nothing behind the eyes," as American Psycho's director, Mary Harron, put it.

23 George Lucas' Dog Inspired Chewbacca

The creator of the Star Wars world would drive around with his large Alaskan Malamute in the front seat of his car, which he described as "bigger than a human being and very long-haired." The affection he felt for the dog was what gave him the idea for the connection between Han Solo and Chewbacca. (Fun fact: He was named Indiana.)

Image via Wikimedia Commons

24 Bill Murray Was Considered for the Role of Batman

In addition to Kevin Costner, Pierce Brosnan, and Mel Gibson, Bill Murray was considered for the role of the caped crusader in the 1989 film Batman. That was, until director Tim Burton came on board and went with Michael Keaton.

25 The Bridge Explosion in The Good, The Bad and The Ugly Had to Be Shot Twice

The big scene in this Spaghetti Western classic—when Blondie and Tuco blow up the bridge leading to the cemetery where the gold is believed to be buried—had to be shot twice. A misunderstanding led to the dynamite around the bridge being detonated before cameras were ready to catch it, requiring the bridge to be rebuilt and the whole thing to be shot again.

26 Scream Was Originally Titled Scary Movie

While the Wayans brothers' spoof of Scream went with the not-so-subtle title of Scary Movie, they would have had to get a bit more creative if the movie they were sending up had stuck with its original title. Now-disgraced former Hollywood producer Harvey Weinstein, who produced the original, heard the Michael Jackson song "Scream" in his car and decided he liked that better than the title that the project had originally been given, and the name stuck.

27 John Landis Loves Casting Other Directors in His Movies

Directors may have a reputation as egomaniacs that don't like to share the spotlight, but John Landis has proven happy to give other directors cameos in his films. Frank Oz and Steven Spielberg both appeared in The Blues Brothers; George Lucas popped up in Beverly Hills Cop III; Into the Night featured Amy Heckerling, David Cronenberg, Jonathan Demme, and others; and Dario Argenta played a paramedic in Innocent Blood.

28 Oscar Winners Used to Be Announced Before the Ceremony

During the early years of the Academy Awards, the organization provided newspapers with the names in advance, with the agreement that they would not publish the names until 11 p.m. Of course, then someone had to ruin it for everyone, when The Los Angeles Times broke this rule during the heated 1940 competition, announcing that Gone With the Wind had won before the statue had been handed out. It led to a rule change that stands today. And for more trivia straight from the Dolby, check out these 30 Oscars Telecast Jokes That Totally Bombed.

29 The Matrix Code Comes From Sushi

Those complex-looking green digits scrolling down the screen in The Matrix may look like mysterious code, but in fact they were symbols from a sushi cookbook, scanned by the movie's production designer.

30 John Travolta Is Actually Pulling the Needle Out of Uma Thurman's Chest

The grizzly scene in Pulp Fiction where Travolta jams a needle into Uma Thurman's chest to try to revive her from her overdose was actually filmed backwards. It allowed to create the effect of the needle actually making contact with the actress—without requiring Travolta to risk puncturing her. For more on movies, check out 37 Movies Every Man Over 40 Should Be Able to Quote.

To discover more amazing secrets about living your best life, click here to sign up for our FREE daily newsletter!