Occasionally, directors let other filmmakers (defined by IMDB as "people who have a significant degree of control over the creation of a movie: directors, producers, screenwriters, and editors") get in on the action during production. Here are seven examples.
1. Edgar Wright // Star Trek Into Darkness (dir. J.J. Abrams)
When Hot Fuzz and Shaun of the Dead director Edgar Wright visited the Sony Studios set of Star Trek Into Darkness, J.J. Abrams invited him to direct one IMAX shot on the production's second unit, which was filming next door. "So I did," Wright tells mental_floss, "and was then late for my next meeting." His shot made up "about 32 frames of action in the finished movie," Wright says. "I did NOT shoot the whole scene, just one single set up of Klingons dying." Wright's shot appears in the action sequence that takes place on the planet Kronos in the Klingon Empire during Khan's capture and arrest.
2. Eli Roth // Inglourious Basterds (dir. Quentin Tarantino)
The climax of Inglourious Basterds features a Nazi propaganda film called Stolz der Nation ("Nation's Pride" in English). Horror director Eli Roth, who also played Sergeant Donny "The Bear Jew" Donowitz in Basterds, directed the film-within-a-film using the pseudonym Alois von Eichberg (You can see a short clip from the DVD extra "The Making of Nation's Pride," with Roth as von Eichberg, here).
While the short film's running time is around 6 minutes, it took three days to complete. "When Quentin cast me, I told him that for the whole six-month shoot, I wasn’t going back to L.A. at any point, but there’s going to be long stretches where my character’s not being used, so if you need anything shot, pieces of scenes picked up to [make] the Cannes Film Festival, let me know," Roth told the Wall Street Journal:
He said that he’d never done that before, but would think about it. Later, he called me and said, get your a– on a plane to Berlin, you’re going to make “Nation’s Pride.” In the script, there are three lines of dialogue from ["Nation's Pride"]. Quentin said he would shoot that, but I need shots of guys shooting. We only had two days, so I asked to fly out my brother Gabriel, and I promised him that we’d get it done, and in two days, we got 140 shots of 20 guys running around in vignettes.
Tarantino was so pleased with the results of those first two days that he gave Roth a third day to shoot with Daniel Brühl, who played Nazi sniper Zoller.
3. Terry Gilliam // Monty Python and the Meaning of Life (dir. Terry Jones)
Originally intended to be an animated sequence at the end of Part V of Monty Python's The Meaning of Life, Terry Gilliam convinced the comedy troupe to make "The Crimson Permanent Assurance" a live-action sequence instead. Gilliam made the sequence bigger and bigger, and its running time jumped from 6 minutes to a whopping 30 minutes. The director was able to cut the sequence down to 16 minutes, and it was ultimately placed in front of The Meaning of Life as its prologue.
4. Don Bluth // Xanadu (dir. Robert Greenwald)
During post-production on Xanadu in 1980, Electric Light Orchestra—which created music for the film—wanted Universal Pictures to incorporate "Don't Walk Away" into the musical. Although the studio agreed, there was no place to put it in the final version. So Xanadu producer Joel Silver brought animator Don Bluth and his producing partner Gary Goldman onto the project to create an animated fantasy sequence featuring "Don't Walk Away," which would bridge two scenes.
Universal gave Bluth—who was in the middle of directing the animated film The Secret of NIMH—12 weeks to animate the fantasy sequence. He took a small team to his house and for three months—12 hours a day, seven days a week—they animated the sequence in Bluth’s garage while the rest of his crew produced The Secret of NIMH at the studio.
5. Aaron Sorkin // The Social Network (dir. David Fincher)
On the last day of shooting on The Social Network, director David Fincher left the set early to give screenwriter Aaron Sorkin the opportunity to direct the last shot of the film. Although the scene Sorkin directed was a small transitional scene, which featured college students discovering Facebook for the first time, the screenwriter got to say "That's a wrap!" on The Social Network's production.
6. Quentin Tarantino // Sin City (dir. Robert Rodriguez & Frank Miller)
As a favor for Tarantino, director Robert Rodriguez scored Kill Bill Volume 2 for $1. In return, Tarantino agreed to shoot one scene in Rodriguez's next film, Sin City, for the same amount. The scene Tarantino directed featured Dwight (Clive Owen) talking to a dead Jackie Boy (Benicio Del Toro) while driving. Although Quentin Tarantino only shoots his movies using real film, he agreed to shoot Sin City using digital cameras because he wanted to get some hands-on experience using the filmmaking technology.
7. Kazuto Nakazawa // Kill Bill Volume 1 (dir. Quentin Tarantino)
In Kill Bill Volume 1, Quentin Tarantino turned to Production I.G. in Japan to bring "Chapter 3: The Origin of O-Ren" to life. Kazuto Nakazawa directed the seven-and-a-half minute animated sequence, which follows the early years of assassin O-Ren Ishii before she became a member of the Deadly Viper Assassination Squad and later the "Queen of the Tokyo underworld." Katsuji Morishita, Animation Producer at Production I.G, recalled that "A person in charge of Japanese casting and staff coordination for Kill Bill informed us of Quentin's strong request for IG to work on the animation sequence, and then later Quentin himself came to our studios to meet with us in person":
He already had the image and style in mind, and wanted us to make the animation based on his script. He actually acted out the performances of the characters to be animated in front of us. There were 4 sequences in all, and the production period was 1 year. Those 4 sequences would've been extremely difficult to make in live action. Even if it had been possible, it would've taken tremendous amount of budget and work.
Production I.G. is the animation studio behind seminal Japanese anime such as Ghost in the Shell, Blood: The Last Vampire, and the Neon Genesis Evangelion movies.
BONUS: Heath Ledger // The Dark Knight (dir. Christopher Nolan)
In The Dark Knight, The Joker kidnaps Batman impersonators and threatens to kill the people of Gotham if the real Batman doesn't unmask himself. He releases a video to the local news revealing his threats to Batman and Gotham. According to Christopher Nolan, Heath Ledger directed the threatening video. Cinematographer Wally Pfister set up lights for the scene and Nolan gave Ledger a camera and told him to do whatever he wanted to do for the scene. Ledger shot multiple takes in different ways to play around with the scene, but it always fell in line with The Dark Knight's overall story.