The creative process for every movie and every filmmaker is different, but it's often said that screenwriters should write what they know, because it'll bring an undoubtable honesty to the material.
And yet, sometimes inspiration comes from the most unexpected of places, ensuring that audiences won't ever be able to figure out how these filmmakers came up with these terrific and memorable scenes.
Sometimes it's a case of a writer translating their own personal horrors into an elevated antagonist on screen, maybe they paraphrased an iconic line from another artistic medium entirely, or they could've even just scoured the depths of YouTube in the quest for authenticity.
These are just a few examples of the hugely unexpected influences behind these largely unforgettable movie scenes, each of which has a wonderfully strange and left-field origin story.
In some instances it was mere good fortune that things happened as they did, while in others the filmmakers smartly employed their media literacy to influence the current project they were working on.
Looking at these scenes, though, you'd almost certainly never guess where the ideas came from...
10. The Writer's Crohn's Disease Inspired The Chestburster Scene - Alien
Alien's chestburster scene is one of the most unforgettable moments in cinema history, when poor Kane (John Hurt) learns the hard way that he's been impregnated with a xenomorph - which promptly explodes out of his chest at dinner.
Though the scene feels horrifyingly otherworldly, it's also so viscerally disturbing that it almost feels as though it had to be inspired by something tangible, right?
And that's absolutely the case, as Alien writer Dan O'Bannon mentioned numerous times that the chestburster scene was written as an homage of-sorts to his experiences of living with Crohn's disease, an inflammatory bowel condition.
O'Bannon suffered with his then-undiagnosed illness while writing Alien, and later described the digestion process as "something bubbling inside... struggling to get out."
And so, O'Bannon's real-life gastrointestinal discomfort laid the groundwork for one of the most brilliantly horrific scenes we've ever seen. Sadly, complications from Crohn's disease claimed O'Bannon's life in 2009.