It Can Think

"Ripley: [Medical is plunged into darkness] They cut the power...

Hudson: What do you mean THEY cut the power? How can they cut the power, man? They're animals!"

- Aliens

""They never attacked the same place twice. They were testing the fence for weaknesses. Systematically. They remember.""

- Robert Muldoon, Jurassic Park

Our heroes are battling the fearsome Monster of the Week. Maybe it's got acid for blood, or More Teeth Than the Osmond Family, or can violate the laws of physics with ease. But gradually our heroes realise something even more terrifying. This creature isn't just some mindless predator. In fact, it could be just as smart as we are...

During discussions of this trope, the building and agricultural activities of ants may come up.

See also Super-Persistent Predator. Monster Is a Mommy is similar in terms of humans underestimating the motives of "monsters".

Smarter Than You Look and Obfuscating Stupidity are the human equivalents.

Anime & Manga

 * In Bakugan Battle Brawlers, the Bakugan (actually aliens from another world turned Card Game) are actually sentient beings who had their self-awareness suppressed due to negative energy. When they regain their sanity, the forces of darkness try to crush them...
 * In the New Vestroia season, there is actually a government conspiracy lead by the King of the Vestals to keep the fact that Bakugan are self aware a secret from the rest of the population...
 * The ELS in Gundam 00 a Wakening of The Trailblazer are at first somewhat single-minded and simplistic in action, and some of the characters in the series remain unconvinced that they are truly sentient until, near the end, the ELS are observed adapting their tactics and countering the humans' strategies in battle. One character even exclaims "They're learning!"

Comicbooks

 * In Robert Kirkman's Destroyer miniseries, Keane battles a giant monster and brutally rends it limb from limb with his inhuman strength. Later he reveals that only after he'd torn its tongue out did he realize it was intelligent and meant no actual harm.

Films

 * The unnamed xenomorphs in the Alien series, most notably in the above-mentioned scene in Aliens where the power is cut off moments before the aliens attack. In a later scene the Queen Alien clearly appreciates the danger Ripley presents to her eggs, indicating for her warriors to back off when Ripley threatens them with a flamethrower. She's also able to operate the lift to pursue Ripley. In Alien Resurection the captive xenomorph immediately realises the connection between the blasts of cold-gas that hit it and the Big Red Button, backing off the instant the scientist moves to hit it a second time. This later serves to bite the ass of a security mook. Likewise the aliens wait till communications are cut off (during security's fight with the mercenaries) before implementing their escape.
 * They don't get that they're all about to be vapourised by the overloaded atmospheric processor, though...
 * The Alan Dean Foster novelisations bring up this trope several times. Ash suggests they try communicating with the creature as it might be intelligent. The second book has Bishop bringing up the ant analogy and pointing out that the aliens have nested themselves in the one place the humans can't destroy them without destroying themselves (next to the cooling units of the fusion-powered atmosphere processor). And Aliens 3 had the xenomorphs actually reading the signs outside their cells, which kind of spoils the whole mystery.
 * Jurassic Park. Muldoon demands that the velociraptors be killed as they're far too intelligent; testing the electric fence for weaknesses (but never the same spot twice, "They remember," he warns) before they were moved to their high-walled prison. They seem to realise when the power is cut and claw their way through the electrified wire at the top. Even Muldoon underestimates their intelligence -- as he's stalking one velociraptor, another ambushes him from the side. His Famous Last Words are a genuinely admiring, "Clever girl...."
 * "We'll be all right as long as they can't open doors."
 * Done even more explicitly in Jurassic Park III, where it's implied the raptors' intelligence is improving. At one point, two characters are pinned behind a mesh door by a raptor. After trying in vain to get at them, it looks up at the gap between door and ceiling and begins climbing the door. There's another scene where the raptors leave one injured man alive and hide nearby, waiting for the other humans to come out of hiding to help him. And that's not even mentioning the revelation that the raptors have their own language.
 * Subverted in Jurassic Park II, though, where they're outwitted repeatedly by tricks a dog wouldn't fall for.
 * Jaws. The shark hunters finally realize that the shark is hunting them.
 * Deep Blue Sea. An underwater facility housing intelligent sharks. They even (possibly) learned how to turn an oven on while one of the humans was in it.
 * Day of the Dead. Captain Rhodes is seriously freaked out when the Mad Scientist demonstrates that zombies can remember how to use objects from their previous lives as humans. Such as a Colt .45 pistol.
 * In Land of the Dead, the zombies become even smarter. The leader of the zombies, Big Daddy, learns how to use a machine gun(and teaches a female zombie how to use it), the zombie horde learns to ignore the "sky flowers"(fireworks) that the humans use to distract them, and one of the undead prove mentally competent enough to chop the hand off of a soldier who has just pulled the pin on his grenade.
 * And the ending is a remarkably hopeful example of this trope, since the zombies look at people who are still alive...and keep on shambling forward, taking no interest in attacking them. Apparently they became smart enough to get over their bloodlust.
 * In Tremors, the Graboids can not only think, but learn very quickly, to the dismay of the citizens of Perfection. Though they start out pretty much just grabbing at whatever's walking around, and smashing through things, later on they dig a trap, and one even figures out the dynamite-on-a-string trick.
 * Subverted, though, in the second movie, after the Graboids metamorphose into the next stage of their life cycle, three-foot-tall raptor things called Shriekers. Burt, who's dealt with the Graboids before, keeps mentioning their learning abilities as explanation for why the power and communications are suddenly cut off, and their escape vehicle's engine is destroyed. Later on, however, it turns out they were just attacking whatever was displaying heat. As one character put it, "You mean they're acting so smart because they're so stupid?"
 * And in the third film El Blanco, an albino Graboid that can't transform into a Shrieker, has gotten smart enough to understand that Burt can't kill until it comes onto his property.
 * Super 8 involves an alien creature that
 * The unfortunate campers in The Ruins realize the plant-like entity they're trapped with is mimicking their voices to lure them into a trap.
 * In the book it first mimics a cell phone ringtone further inside the ruin because it knows humans will go to that noise.
 * It does that in the film too, when it learns of one girl's strong desire to cut herself, and proceeds to repeat her own words to her "I want to cut, I want to cut I want to cut IWANTTOCUT!"
 * Jumanji: "The game thinks?" Yes, Sarah, the reality-warping game that makes everything try to kill you thinks.
 * Rudy the albino baryonyx in Ice Age 3 is smart enough to hold a grudge against an individual weasel, named Buck.
 * Buck specifically, or just all small furry things (of which Buck is the only example most of the time)?
 * In the 2007 film remake of I Am Legend, Robert Neville ends up
 * The alternate ending also shows that
 * In the film version of Starship Troopers, the humans just quickly assume that the Bugs are dumb, mindless animals, and just the idea of them being capable of intelligent thought is incredibly offensive. However, the humans learn their lesson once the Bugs spring a massive trap and repel the initial human invasion force. It's later revealed that they are being led by extremely intelligent "Brain Bugs", a leadership caste.
 * Godzilla has shown a surprising amount of intelligence in several films.
 * At one point late in Deep Rising, the monsters start herding the remaining humans towards their feeding area.

Literature

 * I Am Legend - starting with the scene where they apparently set a trap for Neville. The discovery that the monsters are intelligent causes the protagonist to realize they're not monsters... he is. However, the revelation is more from the fact that they show compassion for each other than from their intelligence.
 * The Day of the Triffids by John Wyndham. The exact level of intelligence of the genetically-engineered Man Eating Plants is a subject for debate, with the first-person protagonist (who worked on a triffid farm) rubbishing the idea that triffids are intelligent -- after all, dissections haven't found anything remotely like a brain. Others are not so sure. One man points out that the triffids escaped from their farms within hours of everyone going blind. In another scene a triffid is waiting outside the very door which a person would run out of if they heard someone driving down the road.
 * One of the protagonist's former (he's presumably blinded and then killed like most other people), who also happens to be a worker at the same Triffid farm knows that they're intelligent, and has been trying to decipher their language (rattling stick-like limbs against their hollow stems). He also notes that they always go for the eyes, having figured out that this is humanity's greatest strength, that is intelligence.
 * At The Mountains Of Madness by HP Lovecraft. The expedition to Antarctica uncovers some fossils of what they assume are prehistoric plants and begin dissecting them. The Narrator later discovers the camp wrecked, and the dogs and scientists all killed except for one missing man, who they assume went insane. It's only when they find his dissected body that they realise the horrible truth -- the so-called fossils are actually sentient aliens capable of hibernating for millennia, and once had a civilization superior to man's.
 * Variation in the Sword of Truth books. We're told early on that short tailed gars are more intelligent than the long tailed variety, and Zedd even has a brief conversation with one (consisting of threatening it, asking its name, and sending it to kill their pursuers), but even then they're mostly treated like animals. In later books, however, it turns out they're quite intelligent, and a whole herd of the buggers pulls a Heel Face Turn (or at least agrees to stop eating humans). It took them how long to realize the talking monsters were smart?
 * In Jeff VanderMeer's Ambergris-stories many characters express scepticism about the sentience or abilities of the Graycaps, but it's quite clear to the reader that they are quite possibly superhumanly intelligent and extremely dangerous when they want to be. The dual narrators of Shriek: An Afterword make a pretty good case of this being pure denial that the sceptics pursue to protect their own peace of mind.
 * Inverted in The War Against the Chtorr, where all the evidence of the Alien Invasion is that there must be some intelligence behind it, yet there's no sign of spaceships or any other means of crossing intersteller distances. The Chtorran gastropedes are assumed to be behind things, yet their intelligence is that of the idiot savant -- they're very good at opening locks and can somehow communicate over distances, yet little else. The series appears to be implying that.
 * The Museum Beast/Mbwun from the novel and movie The Relic is able to recognize traps, hide bodies, and do what it can to stay out of sight from humans, justified by the fact that it.
 * When the heroes in the Codex Alera first come up against the Vord, it seems like it's going to be a case of "send in the army to exterminate the nest of mindless monsters." Unfortunately for them, it turns out that the Vord aren't just intelligent, but brilliant. Heck, the Queen
 * In The Gnome's Engine, the townsfolk of Hob's Church have been trying to wipe out the local burrowing hobgoblins, considering them unintelligent, destructive pests. When a device under construction is sabotaged, one resident speculates that the hobgoblins did it, thinking it to be another hobgoblin-killing booby trap. One of the heroines calls him out on this ("They thought it was?"), and the accusor is horrified to realize that he, himself, isn't as convinced that hobgoblins are dumb animals as he'd believed..
 * Subverted in World War Z, where the mercenary at the Long Island celebrities' fortress hears that their attackers can move quickly, and is frightened by the possibility that the zombies might think, too. It's a subversion because.
 * Non-monster variant: In Mrs Frisby and the Rats of NIMH, we actually see this trope take effect upon Nicodemus in the laboratory as his intellect improves. Later, the sapient rats go to considerable lengths to avert this trope from their human pursuers' perspective, destroying all evidence of their more civilized lifestyle.
 * In the Myth Adventures novels, the main character's pet dragon Gleep seems from his perspective to be roughly on the same intellectual level as a puppy. Later novels show things from the dragon's perspective, and reveal both that it is quite intelligent and that it considers the main character to be its pet.
 * Subverted in Stephen Baxter's Evolution, in the first flashback. There's mention of a dinosaur that's smarter than the others, but all this means is that it's "smart enough to go insane" - it submerges its survival instincts in order to hold a grudge against one of humanity's ancestors for eating its eggs.
 * In Brains: A Zombie Memoir, some of the human antagonists react this way to the protagonists, who are among the few zombies capable of intelligent thought.
 * Non-monster example: the ending of Jingo suggests that the Curious Squid are somewhat civilized and either built for themselves or adapted to living in the buildings on Leshp. They can't figure out why their city disappears above the sea every once in a while, though.
 * In Phantoms, there's a very nasty Oh Crap moment when the characters figure out the Eldritch Abomination has human-level intelligence and awareness, and is terrorizing them For the Evulz.
 * In Phantoms, there's a very nasty Oh Crap moment when the characters figure out the Eldritch Abomination has human-level intelligence and awareness, and is terrorizing them For the Evulz.

Live-Action TV
"EMH: Judging by these bio-scans the organism's been devouring life forms for a bit longer than thirty-nine years. I'd estimate it's at least 200,000 years old.
 * In the Star Trek episode "The Devil in the Dark", Spock deduces that not only is the monster intelligent, it has a valid reason for killing the miners. It turns out that the "crystals" the miners are collecting are actually the monster's eggs. Fortunately, the creature, called a Horta, is able to bargain with the humans to arrive at a mutually agreeable compromise.
 * Star Trek Voyager ("Bliss"). Voyager encounters a huge space-dwelling alien that can create illusions in the minds of starship crews so they fly right into its maw.

QATAI: The intelligent always survive.

EMH: I wouldn't go that far. It appears to operate on highly-evolved instinct. I haven't detected any signs of sentience.

QATAI: Oh, he's intelligent, all right. Smart enough to fool your crew into taking you offline."


 * The Island in Lost.
 * The Smoke Monster too. And oh is it clever.

Tabletop Games
"Chapter 14: "This abomination thinks, somehow. It perceives, it decides, and it acts. Yet it does not live..."
 * This is quoted in GURPS: Magic: Magic 4th Edition. Page 100, Chapter 14 (Knowledge spells). It's played for horror here. The funny thing is that it's mentioned again in Chapter 17 (Meta-Spells) on page 121, where the actual enchantments are explained as well as how they work, and again in Chapter 24 (Technological spells), where the reaction in Chapter 14 is played for laughs.

Chapter 24: "My cell phone does that." "Well, yeah, but this doesn't have any mana chips in it or anything. It's all spells and analog enchantments." "Oh. So?" "I dunno. I guess that used to be a big deal...""

Video Games
""It's constructing a rudimentary weapon!"
 * The X in Metroid Fusion, as Samus and the computer discover their capacity for intelligence over time. To the point of claiming a scientist so they can set the station's core to meltdown, destroying all of Samus's upgrade access points, and stealing an upgrade themselves.
 * Not to mention the fact that the icy, blue X which once targeted Samus for her newly-found weakness to the cold (due to her now part-Metroid DNA), start to run away from her soon after she recovers the Varia suit, which negates this weakness.
 * but not before a few of them suicide dive you, then the others flee when they see it's not hurting you anymore.
 * The similarly-inspired Scurge in Scurge Hive.
 * Everyone thought the Voltigaunts of Half Life were just dumb slaves. Turns out, they really aren't in the sequel.
 * Combine Gunships are smart enough to realize that rockets are the only thing capable of harming them, so they accordingly try to shoot any enemy-fired rockets down. Also, a Fast Zombie in Episode 1 will, if you throw a grenade at it, lob the grenade right back.
 * Used in Resident Evil 4 to show you they're "Not Zombies", by using weaponry, setting traps, and cooperating with each other.
 * Occasionally happens in Elder Scrolls Oblivion: you think you've outsmarted a melee-only opponent by climbing on a rock where they can't get up, but then they appear behind you...
 * Given the typical behaviour of NPCs in Oblivion, witnessing this is downright astounding.
 * One of the more terrifying aspects of Penumbra: Black Plague is this trope. The dog/wolf monsters in Overture seemed to just be aggressive beasts. Your first encounter with one of  in Black Plague?.
 * The Shades from Nie R. At the beginning, they seem like mindless monsters. By the end, they're using weapons and armor, and they can sucker the title character into a deadly ambush with one of the Plot Coupons.
 * In Fallout 3, if you're lucky (or not) you learn this little tidbit of information the hard way: Deathclaws open doors.
 * Thankfuly the fact that they can mimic voices to lure you into a trap is only a in-story ablity.
 * Redlight in Prototype seems like your typical zombie plague. In the backstory, however, is the way the first outbreak occurred: after the test subjects - a few citizens of a small town - were infected, nothing happened at all for four years until the scientists who'd expected a spectacular response packed up and let their guard down. At that point every single subject - by then the entire town - suddenly mutated and attacked all at once. The Virus had waited patiently, spreading quietly, for just such an opportunity. It only acts that way when it has a Runner to direct it, though; the rest of the time, it really is your typical zombie plague.
 * And of course the next iteration, Blacklight, is a fully sapient individual, obviously capable of independent thought, speech, planning, and emotions -.
 * In Mass Effect, you come to a space station which was overrun by rachni, and you can read a log where a scientist states "we treated them like beasts, should have treated them like POW's". Mind you, the race is well known to be sentient - although their appearance can certainly deceive.
 * Mentioned in the Dawn of War II: Retribution Tyranid campaign. Though it's well-known to most factions that the 'Nid Hive Mind is extremely intelligent, Imperial Guard troops are horrified to realize "They're using cover! They're supposed to be just animals!" Of course, given the complete, accurate, and useful information usually given to the Guard, it probably was a shock.
 * The Beast from Homeworld: Cataclysm starts "merely" as a ship-consuming techno-organic virus, but having absorbed enough data from the assimilated ships it becomes self-conciousness, learns to synthesize itself a Voice of the Legion from their communication records and becomes smart enough to strike deals with other villains (and even to screw them over).
 * Dragon Age Awakening shows this trope early on with a
 * In The Incredible Hulk Ultimate Destruction, using objects found around the battlefield as bludgeons and projectiles will result in hearing the horrified voices of your assailants as they realize the Hulk is no mere mindless brute.

"It's learning as it goes, sir!""

Webcomics

 * Showed up with the Diamondshell Beetles in Schlock Mercenary -- we, and the mercenaries, perceive them as just big, ugly monsters, but they're actually fairly intelligent, communicate amongst themselves, figure out how to use human weaponry in a surprisingly short amount of time, and see the humans (and, in particular, Sergeant Schlock) as frightening monsters...

Western Animation

 * The fifth episode of Generator Rex deals with a Hidden Elf Village of engineers and scientists trying to build a transmitter/receiver to communicate with the nanites. Then in the next episode,.
 * The Draags from Fantastic Planet hypothesize that the humans they oppress may be intelligent, but regularly exterminate them anyway.

Real Life

 * It is now believed that most complex life forms that aren't plants have some form of decision making mechanism and the ability to adapt to their surroundings. Current research focuses on figuring out how and to what extent each species does these things.
 * Jumping spiders of the Portia genus. They hunt other spiders, and will observe other spiders in their webs until they can gauge how fast they are and how they react to disturbances so that they can determine the optimal strategy to take them down. They will even observe a spider's mating display so they can imitate it and attract another spider to its doom.
 * Since the web vibrations they need to imitate vary from species to species, Portia memorizes different chords, and actually experiments when it encounters a species it hasn't before.
 * In reality, watch any well-made nature show and you will more than likely view 8 to 10 animals that fall well within this trope.
 * A great example would be elephants. The one way most scientists gauge self-awareness is whether or not the subject can recognize their reflection as themselves as opposed to another animal. With animals, it can be a bit tricky to determine as they can't talk. However, one test is to put a mark on the animal which the animal cannot see but will be reflected in a mirror. Elephants have demonstrated recognition of their reflection by exploring the mark on their own head, not the elephant in the mirror, using the mirror to find it. So, elephants are self aware.
 * Great apes, dolphins and horses as well.
 * Chimpanzees in particular may be even more intelligent than we generally give them credit for. Scientists studying chimps in parts of Africa which are still densely forested have recently observed them not only using tools, but actually fashioning some of their own.
 * And quite possibly pigs. Some pigs have been taught to play video games.
 * Add ravens, crows and magpies to the mix - the first non-mammals to confirmed to have this ability, along with rudimentary skills at using tools and cooperating to solve puzzles.
 * Oh, crows are so very smart. A group of crows in Tokyo have figured out how to use cars to crack open nuts that they cannot open on their own. They drop the nuts into the crosswalks, wait for the cars to drive over them, then fly down and eat the interior when the traffic stops. Now, add to this that they are using the traffic lights to time this operation...
 * That's just the tip of the iceberg. As this article shows, they can plan, communicate, remember, and hold grudges. Hitchcock may have had a point...
 * Keas are pretty bloody bright as well, being parrots. In fact as a whole, parrots and corvids are the brightest bird groups.
 * And swallows! Birds nesting near the entry of a Home Depot have figured out how to work the motion detectors to open the doors. They've even figured out that a person is responsible for the doors not working (being locked) and will harass that person until he unlocks the doors. Just. That. Person.
 * Lions are not large enough to take down giraffes on their own. But, lions in some parts of Africa have figured out that if you scare the giraffes so that they run into a road with heavy traffic, the cars will kill the giraffe for you and you can get a lot of tasty dinner rather easily. This is causing serious traffic problems in some areas.
 * Hyenas meanwhile have a complex, simian-like social structure.
 * House pets, especially dogs, have been known to seek help when their owners are in trouble.
 * Dogs that live in the Moscow Subway system can use the trains to get around and have learned the Rule of Cute to get food for the pack. http://www.cracked.com/article_19213_7-animals-that-are-evolving-right-before-our-eyes.html
 * Living in a city with a widespread public transport system, I can add that most passengers won't even be surprised by dogs using the transport and will regard it as more or less normal. Be it the subway, a bus or a tram: dogs know how to get aboard, know where to sit with attracting minimal attention and know to leave at their stop - provided they are allowed on board in the first place.
 * Octopuses. If not given puzzles and toys to keep itself occupied (octopied?), an aquarium octopus will invariably occupy itself by trying to escape. Sometimes they end up in other exhibits. Sometimes they end up eating the other exhibits.