Out of six films in the Alien franchise and two battles with the Predator, the scene fans remember most involves a tiny monster exploding out of a crew member's chest. The chestburster scene from 1979's Alien set the standard for the franchise. Urban legends claim audiences ran from the theater or became sick after watching the scene. Realistic special effects hadn't been around long, making the chestburster entirely unimaginable for viewers.
Alien trivia facts and behind-the-scenes stories often allege the actors had no idea what was going to happen in the scene, but that's not quite true. The cast had read the script and knew a monster would appear; they just didn't know exactly how, what it would look like, or how much guts would splatter in their faces. Though the scene took three takes to get right, the actors' responses were real, adding to the power and renown of the chestburster scene.
Alien combined horror and science fiction in ways never before imagined and won Oscars for its effects and design. There is no doubt everything that went into making the chestburster scene a reality helped earn the film its spot in movie history.
Since CGI - as we now know it, at least - didn't exist in 1979, every special effect element was made to look realistic with physical props and masterful set design. When asked about the making of the chestburster scene, director Ridley Scott noted, "The reactions were going to be the most difficult thing. If an actor is just acting terrified, you can't get the genuine look of raw, animal fear."
He decided to use the live chestburster effect to his advantage by capturing the cast's real responses to it emerging. Scott declined to tell the cast exactly how the effect would work, and when they read about the scene in the script, it simply said, "This thing emerges."
Scott kept the cast in their dressing rooms while the crew carefully set up the scene. Only John Hurt (Kane) witnessed the crew setting up the device around him. Veronica Cartwright (Lambert) recalled, "They take John down in the morning to prep him, and we're upstairs for four hours. We're sitting upstairs, and nobody knows what the hell is going on."
To make the scene as terrifying as possible, Scott incorporated real elements in the chestburster's carnage. "Prosthetics in those days weren't that good. I figured the best thing to do was to get stuff from a butcher's shop and a fishmonger," he explained.
He used pieces of seafood like clams and oysters as the insides of the facehugger, but the chestburster scene required more human-looking entrails. A crew member went to a butcher and returned with a bag of animal kidneys, intestines, lungs, and livers. To sanitize the organs, they washed them with formaldehyde, which, along with the raw organs, made the set smell terrible.
As crew members stuffed the organs into the fake body cavity, Scott took care of little details that would ensure the chestburster puppet looked as realistic as possible. "I remember easily half an hour was spent with him draping this little piece of beef organ so it would hang out of the creature's mouth," executive producer and screenwriter Dan O'Bannon recalled.
As the camera rolled, Hurt writhed in pain on the table, and crew members below the table moved the false chest to match his movements. The rest of the cast drew closer, acting as if they were trying to care for him. A crew member released the tiny alien, which bulged from the chest - but it didn't break through the shirt. Cartwright recalled, "You see this thing start to come out, so we all get sucked in, we lean forward to check it out."
The actors were unnerved by the false start, which pleased Scott, but since the alien didn't burst through, he called for another take. This time, a crew member cut the shirt a little more to allow the alien to pop out. As the cameras rolled again, the actors moved closer, feeling safe and not realizing the full effect hadn't happened yet.
By the second take, the cast knew Hurt's false chest held something waiting to burst out. The alien managed to rip through the shirt, but due to a clog, there wasn't much of a mess to go with it. Scott kept the cameras rolling and instructed the crew to push the alien out several more times. Unfortunately, it still didn't flow as planned and failed to give Scott the explosive effect he wanted.
They decided to stop, fix the blood lines, and try again, especially since the baby alien was now saturated and looked more realistic. Without telling the cast, Scott instructed a crew member to increase the pressure more than initially planned. Though the actors had already seen the alien and knew it would pop out of the chest, they were not prepared for the gruesome final take.