Crocodile (Black Mirror)

The episode was inspired by the series one episode, "The Entire History of You", which featured a personal implant that one could use privately to review their memories. For "Crocodile", they considered what the situation would be like if these memories were not private, developing a "cat-and-mouse type drama" that would highlight the importance of memories, and to what lengths one with a secret would go to hide those memories.[9]

The episode was initially conceived as having a male protagonist, with Andrea Riseborough reading the script to audition for the insurance investigator—called Shazia in the final episode, and played by Kiran Sonia Sawar.[10] However, Riseborough liked the journey of the protagonist and asked if the part could be rewritten as a woman.[11] Both Brooker and executive producer Annabel Jones described the change as interesting, with Jones noting "How often do you see a mother reduced to this level of desperation?"[11][12] Though they questioned whether a woman would have the physical strength to dispose of a body, Riseborough argued that her character could find that strength in desperation. Brooker commented that "the panicking male murderer is practically a trope", so the gender change was "refreshing".[10]

The episode ends with Mia killing Shazia's son, who turns out to be blind, and her murder of him is witnessed by a guinea pig. This was intended as dark humour in the tone of 1996 black comedy thriller Fargo, though the episode had been more serious up until that point. Mia then watches her son in a production of the 1976 musical film Bugsy Malone, which starred Jodie Foster—the director of the preceding episode "Arkangel".[10]

Brooker explained that the title came from an analogy he made in an earlier draft of the script. In its original form, the script had involved a woman that had seen her mother die tragically at the age of two, causing her to become anxious and fearful of the rest of the world. He had compared this to a virtual reality trip down a jungle river with random events. Someone might go down this trip without seeing a crocodile and thus see it as a calm trip, but someone else might be attacked by a crocodile early on, and for the rest of the trip, become anxious and fearful that they are experiencing a "crocodile attack simulator", the same situation as this character. While the script significantly changed over the course of production, the title was not changed.[13]

The episode was directed by John Hillcoat, who described the episode as a "pitch-black comedy of errors". Hillcoat said that "Crocodile" is about "how human beings actually work and how we would respond to something the tech revolution may well bring into our lives".[10]

The memory reader technology was conceived by Brooker with the arcade machine for Space Invaders in mind. Production designer Joel Collins compares it to a slide viewer, contrasting with the thin screens of contemporary devices. After the memory reader was designed, other technology in the episode such as the pizza truck were re-designed with similar box styles.[10]

The episode was shot in Iceland and includes scenes filmed in the Harpa concert hall.[11] Brooker had originally called out for filming in Scotland in his script, but Netflix suggested Iceland as a "more stunning backdrop", according to Brooker.[14] Hillcoat commented that the "cruel inescapable logic" of Mia's actions were suited for Icelandic "strange, vast and primeval landscapes".[10] During filming, Iceland had its largest snowfall in forty years.[14] The scenes involving the pizza van were the worst affected, with shooting taking place over two nights. Snow needed to be continually brushed and special effects teams used heaters and hoses on important areas in frame. A line was added to the dialogue about snow, the intention being that the difference in snow was a consequence of observers' differing memories.[10][14]

Riseborough's performance as Mia was less panicked than Brooker had pictured when writing the episode. Riseborough injured half of her ribcage during her first rehearsal. Hillcoat opined that Mia has ambition as a "deep inner flaw", whereas Jones thought her actions was a "logical inevitability" of her initially protecting her friend Rob. Brooker said that Mia "really turns" when she hides Rob's body, rather than confessing to causing his death. Sawar found the scene in which her character Shazia was killed by Mia difficult to film, and was unable to watch the scene in the finished episode.[10]

In May 2017, a Reddit post unofficially announced the names and directors of the six episodes in series 4 of Black Mirror.[15] The first trailer for the series was released by Netflix on 25 August 2017, and contained the six episode titles.[16][17]

Beginning on 24 November 2017, Netflix published a series of posters and trailers for the fourth series of the show, referred to as the "13 Days of Black Mirror".[18] On 6 December, Netflix published a trailer featuring an amalgamation of scenes from the fourth series, which announced that the series would be released on 29 December.[19]