->''"It's hard to believe that a week ago my biggest problem was finding a job. It seems almost laughable now. But then, things never turn out the way you think they will."''

''Prey'' is a 2002 sci-fi thriller novel by Creator/MichaelCrichton, this time centering around {{Nanomachines}} that have gone wildly out of control and threaten lives, and the main characters must prevent them from getting any more out-of-hand. As is typical for Crichton, [[ShownTheirWork he goes into]] great detail on the technical aspects of the nanotech; mostly, in this case, computer programmming and evolutionary theory.

The story focuses on Jack Forman, a HouseHusband and former computer programmer in distributed systems who is looking for a new job while his wife Julia brings in the cash. Lately things in Jack's life have not been going too well: he was fired from his previous job, cannot find a new one, and to top it all off, his wife has been acting very strangely as of late, working long hours and becoming increasingly hostile and irrational. At the same time, strange things begin happening around the house: rooms are disturbed, the baby comes down with a nasty full-body rash that disappears just as quickly, and there are extra electronic devices around the house he's never seen before. All this comes to a head when he is hired by his wife's company as a consultant on the same project she's recently been so heavily involved in. Eager to get to the bottom of everything, he accepts and is flown out to a remote facility in the Nevada desert...

Not to be confused with the [[Main/{{Prey}} video game]] of the same name.

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* AIIsACrapshoot: Averted. The nanoswarms are simply trying to protect and propagate themselves ([[GoneHorriblyRight exactly what they were programmed to do]]). However, they are also not smart enough to be reasoned with: not true AI.
* BodyHorror: Any time the nanoswarms interact with organic material, it's probably not going to be pretty. Standouts include:
** How the swarms kill. They suffocate the victims by pouring in waves into every orifice until the victim suffocates, then they dissolve the bodies slowly into grey goo.
** What the human hosts look like when the swarms are removed. They are described as looking like they are dying from cancer, cadaverous, with brittle white hair, emaciated bodies, and translucent skin.
* BookEnds: The first and last scenes of the book are nearly identical, word for word. [[spoiler:At the beginning, the scene sounds like everything has GoneHorriblyWrong. At the end, however, the reader knows enough that the same scene they read on the first page is actually a BittersweetEnding.]]
* CrazyEnoughToWork: This is how Jack survives his first two encounters with the swarm, by performing actions so unpredictable that the swarms have trouble reacting to them. In the first case, when faced with the swarm alone, he removes his shirt and becomes a ScreamingWarrior while attacking the swarm with the whipping shirt, and runs straight through it. In the second instance while with a group, he has them 'flock' together to keep them from being picked off one by one.
* DyingAsYourself: Jack is ultimately unable to save Julia, Vince, and Ricky from the swarms, but does manage to remove them long enough destroy the research facility. Considering the state of the hosts when they are removed, it was most certainly a MercyKill.
* {{Foreshadowing}}: [[spoiler:Midway through the novel, Charley wonders if the nanoswarms could affect human brains. Turns out they can.]]
* HeKnowsTooMuch: The reason the swarm intends to murder Jack and Mae. They have successfully infected themselves with a virus that renders them immune to the swarms' possession, and fully intend the warn the world of the swarm's world domination plot.
* HouseHusband: Jack. Not by choice - he's trying to compete in a highly competitive field, in a highly competitive spot (Silicon Valley, to be exact), and his reputation was effectively ruined by being a whistleblower.
* GreyGoo: Discussed, lampshaded, and [[spoiler:played straight in the first climax. The nanites begin targeting organic material (read: flesh of any sort, living or dead), as they need it to make more swarms.]] Played with in [[spoiler:the second climax: the nanites are now smart enough to ''want world domination.'']]
* GoneHorriblyRight: The "wild" nanoswarms. They are doing exactly what they were programmed to do: solve problems about how to survive on their own. [[spoiler:In an attempt to jumpstart their learning process, the corporation released them into the wild, specifically so that they can adapt to high wind. It worked... and then it began eating people.]]
* GoneHorriblyWrong: [[spoiler:The "infector" nanoswarms, which are parasitically controlling humans in order to survive, something they were never intended to do.]]
* HiveMind: The nanoswarms work using distributed intelligence, which isn't ''quite'' this trope, but it is used as a [[LaymansTerms layman's metaphor]] in the book at one point.
* HollywoodScience: The thermite charges used by the protagonists explode violently when ignited, much like a grenade. In RealLife, however, thermite actually burns relatively calmly.
* InfoDump: Blocks of hard science appear at several points. It's a Crichton staple.
* MechanicalEvolution: The reason the swarms are so dangerous is that they've been outfitted with learning and problem-solving algorithms. As such, their behavior becomes steadily more complex and sophisticated as time goes on.
* MechanicalLifeForm: Or as close to one as you can get in hard Sci-fi.
* MyGodWhatHaveIDone: Julia has the reaction when Jack is able to (temporarily) expel the swarm from her body. She realizes the full horror of what she has done, including infecting her children and murdering her colleagues. All she can do is beg Jack to save them.
* {{Nanomachines}}: The focus of the book.
* OrganicTechnology: The construction process for the swarms involves ''E. coli'' bacteria (the techs wanted a thoroughly-documented bacterium to work with). [[spoiler:The "wild" swarms therefore hunt down and kill animals in order to feed the bacteria within them as part of their reproductive process. A few swarms learn how to "benignly" invade a human body to use as a host and survive.]]
* PuppeteerParasite: [[spoiler:It's not entirely clear how much control the infector swarms have over their human hosts, nor how intelligent they are. The infected hosts claim that the relationship is symbiotic, as it grants the hosts increased strength and vitality. However, Jack discovers this is at least partially a lie when he is able to temporarily remove the swarm from Julia, and she is revealed to be a barely alive emaciated husk who begs for death.]]
* ScienceIsBad: Averted. The book mentions numerous useful, revolutionary technologies that could come about with nanotech. It also stresses that the technology is incredibly dangerous, and should be handled cautiously. The company in the novel just did some incredibly ''stupid'' things, which is what kickstarts the plot.
* ShownTheirWork: It's Creator/MichaelCrichton. The fact that it is impossible to quickly build several billion nanobots individually (the "build-time problem") is directly addressed, for one.
* StuffBlowingUp: Thermite, as it turns out, can vaporize a nanoswarm.
* SurveillanceDrone: This was the task the nanotech was commissioned for. By arranging themselves in certain formations, the swarms can turn themselves into "eyes" in order to record images.
* TheSwarm: The nanobots are organized in such units in order to accomplish tasks. [[spoiler:They can kill things by clogging air passageways and letting the ''E. coli'' cause severe allergic reactions.]]
* TheyLookLikeUsNow: The swarms eventually begin to imitate human forms, learning from animals who use mimicry to lure prey near them or to scare off predators. They accomplish this by carefully arranging themselves into humanoid shapes, and aligning their solar panels, reflecting light into the images they need. [[spoiler:Later, another variant of the swarm can mimic humans somewhat perfectly, but only to taunt our hero.]]
* {{Transhuman}}: [[spoiler:Infected!Julia claims that the nanoswarms are forming a symbiotic relationship with humans, but it is horribly clear, when the swarm is stripped away, that they are really killing the real Julia one small bit at a time.]]
* WeaksauceWeakness: Wind. The nanoswarms have to stick very close to the ground whenever wind comes up, or the swarm will disperse and the bots will deactivate.
* XanatosGambit: An unusual version, as it is pulled by the heroes. Jack and Mae manage to place the swarm killing virus into the main assembly line of the facility, which will flood the air of the facility with the virus, but only if the safety system is turned off. While doing this, they also fill the emergency fire sprinkler tank with the virus as well, and light a fire. This places the antagonistic swarm in a brilliant MortonsFork. If the hosts leave the safety systems on, the infected water will flood the facility and kill the swarm, but if they turn the safeties off, the infected air will flood the facility and kill the swarm. Jack aptly sums it up as "Damned if you do, damned if you don't."
* YouAreTooLate: Two examples:
** Jack discovers a way to both temporarily and permanently remove the swarms from their human hosts, but while using the temporary solution, both he and Julia realize that all the hosts are too far gone to save, as the swarms have "eaten" so much of them as to make even moving them next to impossible. He chooses to MercyKill them all instead.
** Jack sets up his and Mae's XanatosGambit to go like this, creating enough of a distraction for the hosts that they don't realize the full extent of the plan.