The greatest finales in the history of holiday movies include heartwarming miracles, uplifting carols, and, in one case, a bad guy taking an iron to the face. Home Alone premiered in theaters just over 25 years ago, and the holiday classic still holds up today. For those of you who’ve ever watched the film's Rube Goldberg machine of a climax and wondered how it was made possible, Slate recently spoke with a few of the creators to get the behind-the-scenes story.

When listing their cinematic inspirations, the makers of Home Alone cited both A Christmas Story (1983) and the decidedly less cheery 1971 thriller Straw Dogs. The movie’s production designer, John Muto, admitted that he expected a few of Home Alone’s more violent gags to get nixed, but they surprisingly all made it into the final cut.

When it came time to film the iconic finale, Muto drew Kevin's “Battle Plan” himself, using his left hand and intentionally misspelling words to make it more realistic for a kid. To stage the sequence, Muto stuck religiously to John Hughes’s tight script. Many of the scenes were shot on a set built inside the closed branch of a nearby high school, which spared the actual house featured in the film from being completely trashed. In order to capture as much of the action as possible, director of photography Julio Macat rigged a pint-sized “bonus camera.” At one point, this was tied to the end of a rope to simulate the perspective of the iron as it swung into Marv’s face. 

20th Century Fox

While it’s hard to sit through Home Alone’s ending without cringing, the production team took careful measures to ensure no one was actually harmed while filming. For instance, the red-hot soldering iron Kevin hangs over the doorknob was actually made from red neon tubing, and the nail that Marv steps on in the basement was spring-loaded to retract beneath his foot. When Joe Pesci’s character has his head set aflame via blowtorch, this also required some clever usage of practical effects. Without the option to use CGI, the filmmakers employed the Pepper’s ghost effect by setting fire to a mannequin and superimposing the image onto Harry’s head using reflective glass.

As for the stunt doubles, they didn’t always get off so easy: Whenever you see the Wet Bandits slipping head-over-heels on some strategically-placed booby traps, it's the actors' two stuntmen who were taking the brunt of the fall. Today in the industry, stunt people will still refer to acting out an exaggerated fall as doing a “Home Alone.”

One gag actor Daniel Stern did have to suffer through was the tarantula scene. When you see Buzz’s spider crawl onto Marv’s face, that’s no special effect: there was no barrier separating him from the eight-legged creature. For the scene, Muto drew inspiration from the moment in the James Bond film Dr. No (1962), where a tarantula crawls onto 007's shoulder. The major difference in that case was that there was a piece of glass separating the spider from actually touching Sean Connery, which makes the scene in Home Alone even more hardcore.

[h/t: Slate]