Roy Batty, the android antagonist played by Rutger Hauer in Ridley Scott's sci-fi masterpiece Blade Runner, does a lot of weird things, including driving a nail through his hand. Released in 1982 (and repeatedly recut in the decades since) Blade Runner is a classic fusion of sci-fi and noir cinema which remains hugely influential. Marrying a thoughtful, complex plot with brutal action and stunning visuals, the film is deservedly beloved by film fans.
But unlike Ridley Scott's earlier sci-fi classic, 1979's brutally simple "haunted house in space" horror Alien, Blade Runner isn't an easy movie to parse on first viewing. The film's plot is as convoluted as any classic film noir and has an added layer of futuristic jargon for viewers to contend with. But beyond even this surface complexity, Blade Runner is a tough film to read because it's got a lot to say about humanity, technology, and the impact of individual lives on the world around them.
Like its sequel Blade Runner 2049, Blade Runner's story is famously difficult to follow, but the reasons behind Roy's self-injury become clearer when placed in context with the rest of the film's overarching themes. The movie is about identity and the search for self in an increasingly automated world, and it's an existential mystery as much as it is a traditional detective story. Roy often acts as a dark mirror to the film's antihero, Harrison Ford's conflicted Rick Deckard, and the moment when he drives a nail into his hand can be seen to underline both the similarities between the characters and their differences.
Okay, so let's get the boringly practical, non-metaphorical reason out of the way first. The anti-villain is dying in the middle of fighting Deckard, with his pale hand exhibiting signs of shutting down as Roy's replicant body gives up on its existence. To keep himself in the fight a little longer, Roy jams a nail into his hand. Depending on how life-like the replicants internal workings are, this will either prompt a release of adrenaline to deal with the pain and thus allow Roy to continue fighting, or it'll start a healing process that will give his extremities a few more minutes of function so he can finish off Deckard before shutting down. So that's the practical reason, but no matter what he does Roy is still shutting down because he's reaching the end of his life cycle. This brings us to the more metaphorical aspects of this scene...
Like all replicants, Roy comes with an expiration date, and boy is he not happy about it. It's Roy's impending obsolescence that sets the typically byzantine film noir plot of Blade Runner in motion, as Deckard is sent to euphemistically "retire" Roy and his fellow runaway replicants when they near the end of their life cycle. Throughout the film, viewers see Roy's journey through the five stages of grief as he copes with his enforced "mortality." Roy is initially driven to violence by his anger, later grieves over the loss of his lover Pris, and eventually comes to accept his fate. In a change from the film's source novel, Philip K. Dick's Do Androids Dream Of Electric Sheep, Roy isn't killed by Deckard but instead takes his own life after his iconic "tears in rain" speech (which, fun fact, was partially improvised by Hauer).
Despite holding his creator hostage in the vain hopes of buying himself some time, Roy is informed that even as an exceptionally strong, smart replicant, he's destined to die. Like fellow sci-fi sacrifice Neo, Roy can't outrun his fate. Roy isn't "mortal" in technical terms as he's not human and his death is predetermined by the company that created him. If he were human Roy would eventually have to die, as all people do. Depending on your philosophical views, it's easy to argue that human lives are as predetermined as Roy's robotic lifespan, particularly in this film's dystopia, whether by fate, destiny, God, or social and cultural conditions, class, etc.
The ambiguous ending is famous for never explicitly confirming or denying whether Deckard is a replicant. But regardless of your reading, there's no arguing Roy uses his hand injury to compare himself to Deckard. He crushed Deckard's hand moments before he cuts his palm open, and he's creating an obvious comparison between himself and the possible-replicant Rick. He's also giving himself a handicap in their fight, bringing the playing field closer to level by taking one of his hands of the equation, too.
Roy sees himself and Deckard as equals, something Deckard struggles with and can't comprehend. In the film's Final Cut, Deckard appears to have a realization while picking up an origami unicorn shortly after Batty self-terminates in his presence. Many viewers read this moment as Deckard realizing that he too is a replicant, something Roy was not-so-subtly hinting at when he gave the pair matching injuries during his last moments alive.
Roy's decision to skewer a nail through his palm also has some pretty explicit religious symbolism. The phenomenon of "stigmata" refers to scars or injuries, self-inflicted or otherwise, which resemble the marks left on Christ's body after he was nailed to the cross at Calvary. Scott may never get his scrapped Gladiator 2 resurrection, but in this interpretation, another of the director's characters can be read as a Christ figure with Roy's injury being an act of self-sacrifice. The replicant dies for others to live as his death prompts Deckard to reflect on his mortality and come to the aforementioned realization. I
f you buy into the interpretation that Deckard is a replicant too, then Roy dies so Rick can live freely, escaping the bonds of their life cycle. But even if you don't buy that Deckard's a replicant, Roy fulfills the Christ role here as he's living his life to the fullest while a Judas figure wastes his limited lifetime tracking and policing him. Roy's death frees Deckard from doing the bidding of the Tyrell Corporation and leaves him able to find his path.
