Horror movies are so often remembered more for their villains than their heroes, for the grotesque and terrifying monsters - whether human or alien - which terrorise the protagonists.
And so, beyond the script or director, creature design is a hugely important part of crafting a memorable horror movie icon which burrows itself deep into viewers' psyches.
While it's tough to imagine these 10 legends of the genre looking any other way, fate nearly had other plans in store, by way of these earlier concept designs.
Whether they were switched out before shooting began or the filmmakers had to frantically change things up during or even after principal photography was completed, in each case these indelible genre mainstays almost looked markedly different.
In some cases it's clear that the original design also would've worked for the movie's intended style and tone, while in others it's evident that an eyebrow-raising disaster was avoided by ditching these often eccentric and extreme alternate designs.
For better or worse, these films would've all been forever altered had those in charge stuck the course with their original designs...
10. The Xenomorph - Alien
There are few movie monsters - if any - more viscerally iconic than that of Alien's Xenomorph, the discomfortingly psychosexual masterwork of surreal artist H. R. Giger.
But before Giger put his indelible stamp on the creature, screenwriter Dan O'Bannon and artist Ron Cobb took their own stab at designing it, resulting in this more conventionally alien piece of concept art.
The four-legged iteration of the monster was a far cry from the more sleek, elegant final design, and above all else, it's tough to imagine anyone ever thinking of this Lovecraftian monstrosity as anything close to the "perfect organism."
Ultimately Giger took over and lent his unique vision to the project, resulting in one of the few truly original monster designs in Hollywood, and one which continues to incite fear over 40 years later.