Genetic engineers Clive Nicoli and Elsa Kast hope to achieve fame by splicing animal DNA to create hybrids for medical use at the company N.E.R.D. (Nucleic Exchange Research and Development). Their work previously yielded Fred, a dog-sized vermiform creature intended as a mate for their female specimen, Ginger. After successfully mating them, Clive and Elsa plan to create a human-animal hybrid that could revolutionize science. Their employers Joan Chorot of N.E.R.D. and William Barlow forbid them from doing this. Instead, they are to find and extract proteins used for commercial drug production from Fred and Ginger. Clive and Elsa, however, disobey their superiors and pursue their own agenda in secret, developing a viable prepubescent female creature.
Although they had planned to terminate the hybrid before it reached full term, Elsa persuades Clive to let it live. They discover that she is aging at a vastly accelerated rate. Elsa discovers that the creature is undergoing mental development such as that of a young human child. Elsa names the creature "Dren" after the creature spells out NERD, having seen the letters on Elsa's shirt.
After moving Dren to a new location for fear of discovery, they find she has a dangerously high fever. In an attempt to save her they place her in a large industrial sink full of cold water. Later on Clive completely submerges Dren in the sink, and in doing so discovers that Dren is amphibious.
While studying Dren, Elsa and Clive neglect their work with Fred and Ginger. At a highly publicized presentation of their work, Fred and Ginger savagely fight to the death. It is subsequently discovered that Ginger had spontaneously changed to a male, but Elsa and Clive failed to notice because they were focused on Dren.
Elsa forms a motherly bond with Dren. After Dren jumps on Clive's brother, Gavin, they move her to an isolated farm. There, Dren displays carnivorous tendencies and retractable wings. She grows into adolescence and becomes bored with being locked up in the barn, but Elsa and Clive fear that letting her outside might lead to her discovery. Clive realizes that the human DNA used to create Dren was Elsa's, not from an anonymous donor as Elsa had told him. After Dren exhibits dangerous misbehavior Elsa restrains Dren and removes her stinger, using it to synthesize the protein that Elsa and Clive had been searching for.
Meanwhile Dren and Clive have developed a mutual attraction. Elsa discovers them having sex in the barn and becomes upset. Clive accuses Elsa of never having wanted a "normal" child because of her fear of losing control; instead she chose to raise one as an experiment, where control could be assured. Deciding the only solution is to terminate Dren, they return to the farm and find Dren apparently already dying.
William Barlow discovers human DNA in Dren's protein samples and arrives to investigate. Elsa tells Barlow that Dren is dead and buried behind the barn. However, Dren, having metamorphosed into a male, rises from the grave and attacks the group, killing Barlow and Gavin before raping Elsa. Clive attacks Dren to save Elsa, but Dren overpowers him. Elsa intervenes and is about to kill Dren, but she hesitates, which allows Dren to kill Clive. Elsa then kills Dren.
Elsa is later informed that Dren's body contained numerous biochemical compounds for which the company has begun filing patents. Joan offers Elsa, now visibly pregnant with Dren's baby, a large sum of money to go through with the pregnancy, which Elsa accepts.Adrien Brody as Clive NicoliSarah Polley as Elsa KastDelphine Chanéac as DrenBrandon McGibbon as Gavin NicoliSimona Maicanescu as Joan ChorotDavid Hewlett as William BarlowAbigail Chu as Child Dren
Splice was written by director Vincenzo Natali and screenwriters Antoinette Terry Bryant and Doug Taylor. The script was originally meant to follow up Natali's Cube (1997), but the budget and restricted technology hindered the project. In 2007, the project entered active development as a 75% Canadian and 25% French co-production, receiving a budget of $26 million. The director described the film: "Splice is very much about our genetic future and the way science is catching up with much of the fiction out there. [This] is a serious film and an emotional one. And there's sex... Very, very unconventional sex. The centerpiece of the movie is a creature which goes through a dramatic evolutionary process. The goal is to create something shocking but also very subtle and completely believable."
In October 2007, actors Brody and Polley were cast into the lead roles. Production began the following November in Toronto. It was aided by Telefilm Canada's funding of US$2.5 million. Filming took place in Toronto and concluded in February 2008.
In an interview, when asked if there would be any sequels, Natali responded, "I don't think so. It could happen, but it would have required the movie to make a lot of money in the States, but even though the ending of the film appears to be setting up a sequel, that was never my intention. All of my films end with a question, and somewhat ambiguously, and they always imply the beginning of another story, I like to leave the audience with something to ponder."
The film premiered on October 6, 2009 at the Sitges Film Festival, where it won "Best Special Effects" and was in the running for "Best Film", and was part of the 2010 Sundance Film Festival in Park City, Utah. After a bidding war with Apparition, The Weinstein Company, Newmarket Films, First Look Studios, Samuel Goldwyn Films, and Sony Pictures Worldwide Acquisitions, Dark Castle Entertainment purchased the US rights to the film and the worldwide rights to any possible sequels in February 2010, thinking they "found the next Paranormal Activity". The film received a wide release in the United States on June 4, 2010, with Warner Bros. as distributor. The trailer was attached to two other Warner Bros. movies, The Losers and A Nightmare on Elm Street.
Splice was released on DVD and Blu-ray on October 5, 2010 in the USA and on November 29, 2010 in the UK.
The film has received generally positive reviews from critics. Review aggregation website Rotten Tomatoes reports that 74% of critics have given the film a positive review based on 184 reviews, with an average score of 6.6/10. The site's critical consensus states: "It doesn't take its terrific premise quite as far as it should, but Splice is a smart, well-acted treat for horror fans." Review aggregator Metacritic gave the film an average score of 66 out of 100 based on 35 reviews, indicating "generally favorable reviews."
The Flick Cast said "Splice is funny, frightening, and shocking all at once. It's a disturbing commentary on where science is heading, and it is not easily shaken off once you leave the theatre."
Manohla Dargis' review from The New York Times was highly positive, with stating "Mr. Natali, whose earlier films include “Cube,” hasn’t reinvented the horror genre. But with Splice he has done the next best thing with an intelligent movie that, in between its small boos and an occasional hair-raising jolt, explores chewy issues like bioethics, abortion, corporate-sponsored science, commitment problems between lovers and even Freudian-worthy family dynamics."
Andrew O'Hehir from Salon.com said "Dark, sleek, funny and creepily infectious, the genetic-engineering horror-comedy Splice is a dynamic comeback vehicle for Canadian genre director Vincenzo Natali, who made a splash a few years ago with Cube."
Lisa Schwarzbaum from Entertainment Weekly gave the film an A- and stated "The outstanding creature effects by Howard Berger only get more astonishing as Splice splits into an eerie horror picture, then divides again into something out of Rosemary's Baby."
Roger Ebert from Chicago Sun-Times gave the film 3 out of 4 and stated "The script blends human psychology with scientific speculation and has genuine interest until it goes on autopilot with one of the chase scenes Hollywood now permits few films to end without."
Peter Travers from Rolling Stone said "Played as a child by Abigail Chu and as an adult by Delphine Chanéac, Dren morphs into a special-effects miracle, sexy and scary in equal doses." and gave the film 3 out of 4.
Lou Lumenick from New York Post described the film as "Smart, scary — and at times very funny — horror movie."
Richard Roeper panned Splice, calling it one of the worst movies of 2010. He gave the film a D+ calling it "ridiculous" but giving it credit for trying to be different.
The film opened on June 4, 2010 in wide release to a $7.4 million opening weekend in 2,450 theaters, averaging $3,014 per theater.
Splice won the 2011 Telefilm Golden Box Office Award, CAD$40,000, for being the highest-grossing Canadian feature film in English in 2010.
The film was nominated for Best Science Fiction Film at 37th Saturn Awards, but lost to Inception, another film from Warner Bros.