Marshall compared the change to the ending of The Texas Chain Saw Massacre, saying, "Just because she gets away, does that make it a happy ending?" The ending is featured on DVD as an "unrated cut" in the United States. Creature design In the film, the women encounter underground creatures referred to as crawlers by the production crew. Marshall described the crawlers as cavemen who have stayed underground. The director explained, "They've evolved in this environment over thousands of years. They've adapted perfectly to thrive in the cave. They've lost their eyesight, they have acute hearing and smell and function perfectly in the pitch black. They're expert climbers, so they can go up any rock face and that is their world." Filmmakers kept the crawler design hidden from the actresses until they were revealed in the scenes in which the characters encountered the creatures, to allow for natural tension. Conception Director Neil Marshall first chose to have a dark cave as the setting for his horror film The Descent then decided to add the element of the crawlers, describing them as "something that could get the women, something human, but not quite". The crawlers were depicted as cavemen who never left the caves and evolved in the dark. The director included mothers and children in the colony of creatures, defining his vision, "It is a colony and I thought that was far more believable than making them the classic monsters. If they had been all male, it would have made no sense, so I wanted to create a more realistic context for them. I wanted to have this very feral, very primal species living underground, but I wanted to make them human. I didn't want to make them aliens because humans are the scariest things." The crawlers were designed by Paul Hyett, a makeup and prosthetics creator. Production designer Simon Bowles said that the crawler design had started out as "wide-eyed and more creature-like", but the design shifted toward a more human appearance. Crawlers originally had pure white skin, but the look was adjusted to seem grubbier. The skin was originally phosphorescent in appearance, but the effect was too bright and reflective in the darkened set, so the adjustment was made for them to blend in shadows. The director barred the film's cast from seeing the actors in full crawler make-up until their first appearance on screen. Actress Natalie Mendoza