Sometimes the owner or driver of a vehicle has a certain connection to their vehicle (be it a car or spaceship etc.) and a way to demonstrate that bond is to make the operator the only individual who can make it run. In the hands of someone else it will fail to start or come to a stop after a few seconds without the gentle touch of the person who knows the special trick to starting the engine or all the little adjustments you have to make.
It tends to happen with either the very best or very worst of cars. The Alleged Car is so rotten through that it needs someone with great knowledge of all its faults to keep it going (and sometimes overlaps with Percussive Maintenance when only the owner knows the sweet spot). The Ace Custom Cool Car can also be full of complex gadgets that you need to keep track of. Or maybe it's just so cool it only deserves the really attentive owner.
Related are Empathic Weapon and Loyal Phlebotinum, which typically will only work for the owner. (Though it is not unknown for a character using this trope to talk as if that trope was in play — the difference is that those tropes are for devices that refuse to work for anyone else while this one is for devices that malfunction without the owner's special touch.) A Black Box is when the "I" in the equation is not present, and the people involved try to bulldoze their way into forcing the something to run, with unpredictable results. Magic Powered Pseudo Science is when the maker is the wizard who did it.
- Eureka of Eureka Seven is at first the only one who can pilot the Nirvash TypeZERO.
- Simon is the only one who can pilot the Lagann.
- This seems to have more to do with the fact that he's the only one with a core drill, not counting Lord Genome, and they might not be interchangeable anyway.
- In addition to the key, the Lagann is attuned to Simon because of his latent Spiral power. Other characters develop Spiral power over time, and eventually get their own Lagann-type mechs in the end, so it's likely that someone else could pilot it if Simon gave them the core drill. The one time he tries, Kamina rebuffs him because he recognizes that Simon is better suited to it.
- Kaneda's bike in AKIRA is tricked up enough that he's the only one who can keep it going. When Tetsuo tries to steal it, it ends up winding down and landing him in trouble.
- Hayato from Future GPX Cyber Formula is the only person who can drive Asurada, since the car has an AI system with a unique security feature.
- Explained as one of the problems with the Zeta Gundam by the time Mobile Suit Gundam ZZ rolls around. By the end of its service life, the Zeta Gundam was so customized and tailored to Kamille Bidan's specs that while Judau and later Roux are able to pilot it with some effort, they can only as much as it's base specs allow. They can't access the biosensor to let it do the crazy things Kamille made it do in Zeta because only his mind could trigger it, even though Judau was an even stronger Newtype than Kamille and later on can make use of his own Double Zeta Gundam's biosensor.
- In Mobile Suit Gundam SEED, Kira is initially the only person on the Alliance's side able to pilot a mobile suit because, as a Coordinator, he has much greater multitasking abilities than a normal human, and mobile suits are too complex to operate without those. Later, Kira is told to place a lock on the Strike's systems that only he can open when they dock at an Alliance base. The reason for this is that the Alliance is heavily racist against Coordinators, and having that lock there gives Kira a bargaining chip to protect himself.
- In Mobile Suit Gundam SEED Astray, the OS of the Red Frame Astray is tailored so that only it can use the Gerbera Straight katana without blowing every servo and gear in a Mobile Suit's arm.
- Mobile Suit Gundam Unicorn: The Unicorn Gundam has been hard-coded with a DNA scanner set to Banagher Links, meaning he is the only person that can pilot it, which is the primary reason the various factions keep him around rather than just stealing the Gundam for themselves.
- Gundam: Reconguista in G: The G-Self only responds to three people: Raraiya Monday, Aida Surugan, and Bellri Zenam. Which is odd, considering that Aida and Bellri had never seen the suit before. Anyone else who sits in the cockpit and presses buttons gets completely ignored. It turns out that it had been coded by its builders to only respond to Raraiya as a security measure for her mission to Earth... but had also been programmed to accept commands from the members of the Rayhunton family, which both Aida and Bellri are, though they didn't know it at the time.
- In GaoGaiGar, the titular mecha could only be piloted by Guy. Originally, anyway.
- It's likely any G stone powered being could use it. It's just that Guy was one of only two around and the other was kid that was too young to use it properly. Gaofaigar on the other hand was fueled by his Evoluder powers which were unique to him (Mikoto's were different) which meant only he could use it.
- In Code Geass, Lelouch's second season mecha the Shinkirou features a scattering energy cannon and the strongest Beehive Barrier in existence. However, it takes an exceptionally smart and quick-thinking pilot in order to draw out their full potential; in the hands of anyone but Lelouch, it's still high tech but not nearly as powerful.
- It's also mentioned that Suzaku is the only person capable of making the Lancelot move, let alone do anything else. Same with Kallen and the Guren SEITEN.
- In Full Metal Panic!, Sōsuke is the first person to pilot the Arbalest, an experimental Arm Slave loaded with black box technology, and is later forced to become its designated pilot since the mech's quirky AI (named Al, with an "L") became calibrated to him and can't be reset because its creator committed suicide. This causes problems in The Second Raid, since Al's eccentric nature (among other things) starts wearing on Sōsuke. It's later mentioned that Al simply won't let anyone else pilot the Arbalest; when Mithril tried, Al kept asking "Where's Sergeant Sagara?" and then shut down and refused to start back up when told that he wasn't around.
- Archie Comics:
- Archie sometimes plays this trope straight, sometimes pokes fun at it. For instance, in one comic, Arch said he couldn't lend the car out to Betty because he was the only one who knew how to keep her running. Oh course, when the car did break down and he couldn't figure out what the problem was, guess who figures out how to fix the jalopy...
- One episode has Mr. Svenson retire and Riverdale High hires a new young custodian for the job, but it's quickly revealed that the utilities and furnace in the school are in such disrepair and so ancient that Mr. Svenson is the only one who can actually keep any of them running without causing actual snowfall in the cafeteria.
- Nancy Callahan of the Sin City story "That Yellow Bastard" has a car so old and in such bad shape that it will stall out on anybody who tries to drive it, except for her. When her kidnapper, the title character, can't get it working, he has to take her to the Roarks' infamous farm on foot, giving Hartigan time to catch up to them and save her.
- In Suicide Squad, Briscoe claimed to be the only one capable of piloting the team's helicopter Sheba. Given how possessive he was about Sheba, and that she seemed to respond to the sound of his voice, no one was ever quite game enough to test his claim.
- Depending on the Writer, the Batmobile sometimes has anti-theft features specifically designed so that no one except Batman can start it. An interesting incident happened during the tail end of Knights End: after AzBats drops into the river, Batman races to the Batmobile (which somehow followed them) and tries to get in. Jean-Paul changed the locks, but Bruce overrode them. He hops in, starts it up... and the Batmobile explodes. He survives and tells Robin (Tim Drake) that he would have done the same thing for an anti-theft deterrent, but not with such lethal intent.
- Wonder Woman's invisible plane used to be referred to as her "robot" plane back when the Amazons were still their Golden Age tech whiz selves and the thing was equipped with a mental radio device which allowed Di, and Diana alone, to control it remotely using her mild telepathic abilities.
- Biff in Back to the Future Part II had a very sweet ride which only he could start the ignition of (to the bemusement of his mechanic). After the Exposition of this in the scene with the mechanic, it's used as a sort of time travel Trust Password by his future self who had come to give him Gray's Sports Almanac.
- It's also notable that the DeLorean's starter motor never stalls out for Doc, only for Marty.
- In 2012, the car that's used to escape from the plane would only start from Yuri's voice recognition.
- The Transporter has his cars equipped with a keypad that requires a correct code to turn the key. The second film starts with a bunch of punks trying to steal his car only to find out that it won't start without the code. And Frank won't give them the code. Then they make the mistake of trying to beat it out of him.
- In Mad Max: Fury Road, the War Rig driven by Imperator Furiosa can only be driven after activating a convoluted sequence of switches under the dash. Which the titular character found out, much to his chagrin.
- In the movie Excalibur, Uther Pendragon drives the titular sword into a random stone so that "no one can wield it but meeeee!" Years later, Arthur, Uther's hidden son, desperate for a sword, easily draws the sword from the stone, proving that he is the right-wise King of England.
- When Mr Gilbreth dies at the end of Cheaper by the Dozen the family sells the car for scraps, seeing how he was the only one able to start it.
- In Corner of a Round Planet this is subverted, but not averted. All Auggies have a custom-built rig that responds to their particular brainwaves. The rigs lose significant efficacy when the wrong driver attempts to use them.
- In Shadows of the Empire, the Millennium Falcon is described as this, with Han Solo and Chewbacca having over-customized the freighter to the point where even Lando (who had heavily customized it himself before ownership changed hands) can't do proper maintenance on it because the circuitry is such a mess. Interestingly, it fits both sides of the trope; it's The Alleged Spaceship to look at it, but one of the best ships in the galaxy with Han Solo flying it.
- Rangers' horses in Ranger's Apprentice can only be ridden if rider asks for permission in specific words mounting for the first time. Anyone who didn't gets a free lesson in doing somersaults.
- James Herriot, after much badgering of his boss Siegfried Farnon, was finally granted a car to do his vet rounds in. What he got was a vehicle that was a potentially dangerous risk even by the standards of the free-and-easy 1930's. note Herriot soon got used to driving a car with no floor under the driver's feet and some distinctly underpowered brakes, which almost had to be manually pushed up hills. But the local garage mechanic almost crashed it while reversing it into the working bay, noting, with typical Yorkshire understatement, that
Your brakes aren't ower-savage, vitnary.''
well.... you did, Siegfried.
- He got an upgrade after Siegfried borrowed and crashed it, demanding to know afterwards who'd bought such a junkyard on wheels.
- Skyward: Spensa's Gran-Gran mentions that her mother was the only one who could make the Defiant's engines run. It turns out that this was literal. Spensa's family are cytonics, and Gran-Gran's mother was the actual FTL drive.
- Knight Rider: Michael Knight gave the explanation that the car's on-board computer could read his fingerprints - it's more plausible than the car having AI.
- Implied in the old Doctor Who episode "The Pyramids of Mars" that only The Doctor can operate his TARDIS. He may have been lying, though...
- The Master sure had no trouble using it, though it may be that only a Time Lord can use it and the Doc is usually the only one around.
- Steven and Leela have both managed to pilot it.
- So has River Song - though it's been both denied and implied (in that order) that the Doctor taught her to drive it.
- Ultimately denied: she was taught by the TARDIS itself.
- In the 2010 Christmas special A Christmas Carol; this time it's not the TARDIS in question but, a device that will save the lives of people aboard an out-of-control shuttle craft in a cloud belt storm. Although it's not a vehicle, it's a machine that controls a planet's clouds. Too bad the only one who can work the controls is a bitter old sod who couldn't give two dumps about what happens to the people aboard. The Doctor gets so fed up with the man's heartless personality that he goes back in time to directly alter that man's past so he doesn't grow up into such a monster. Unfortunately, the Doctor's meddling works too well and the machine no longer recognizes the man because his personality has become remarkably different.
- A partial example occurs in Lexx: Only one person has the "key" to the titular ship (a small Energy Being that embeds itself on the recipient's hand) at any given time and it can only be passed on by the original holder dying or being "brought to the height of sexual ecstasy".
- The rules for this have been inconsistent as in the first installment the original owner transfers the key at will. It may simply be that no one else after him knew how to consciously hand over the key as he hadn't told anyone else before dying.
- Severing the owner's hand seems to work too but if they've given at least one prior command to the ship it still requires their voice to get the ship to even scan the hand (or at least a very good imitation of their voice.)
- Played for laughs on an episode of Cheers. The gang takes a road trip in Cliff's car and crash. Getting the car back on the road requires some things Cliff didn't tell them.
Sam: Cliff, I'm turning the key, but nothing's happening.
Cliff: That's because I've got it rigged up with a Cliff Clavin Anti-Theft System. What I do is I turn the wheel all the way to the left.
(Sam turns the wheel.)
Sam: Got it.
Cliff: And then I turn the key as hard as I can.
(Sam turns the key.)
Sam: Oh dear. Cliff, I just broke off the key in the ignition.
Cliff: I said as hard as I can, Sammy!
- Stargate: A lot of Ancient technology was programmed to only respond to their DNA. As it happens, they interbred some with ancient humans, so a few modern humans have the particular gene the technology is programmed to respond to, and can activate it. Similarly, the Goa'uld programmed much of their tech to only respond to themselves, this time based on detecting naquadah in the blood, which only Goa'uld (and their hosts) will possess. However, someone who was once a host to a Goa'uld will retain that naquadah, so the tech will still accept them despite the absence of an actual Goa'uld.
- The Orks of Warhammer 40,000 have a latent psychic field that allows their vehicles to function in bizarre ways because they believe they can (Red wunz go fasta, planes keep flying until the pilot is informed they ran out of fuel a while ago, etc). So when a non-Ork uses one, it tends not to work. Depending on the Writer, this may be downplayed or exaggerated:
- Sometimes this is presented as total It Runs on Nonsensoleum, such as a Codex entry where some Imperial techpriests opened up a gun they had actually seen an Ork fire and found it was an empty shell full of a few broken parts and some loose bullets rattling around at the bottom.
- Elsewhere it's presented as Orks actually having an inbuilt propensity to build primitive but genuinely workable technology, and the psychic effect just smoothing things out a bit. For example, Ciaphas Cain (HERO OF THE IMPERIUM!) at one point had a sizeable fleet of commandeered ork vehicles for his ragtag refugee army. The techpriest he had along was fascinated by them, as they seemingly shouldn't have worked at all, but most still did work with neither her help nor that of a nearby Ork.
- In the Dark Heresy Spin-Off Only War, Ork weapons can be found and looted on the battlefield, but the rule text makes them explicitly less effective (becoming Reliably Unreliable Guns) when used by non-Orks.
- In Pathfinder, the gunslinger class starts off with a basic gun which only they can use properly, and can therefore only be resold for scrap. This is something of an Obvious Rule Patch, since firearms are among the most expensive non-magical items — the ones available as starting weapons should cost 1000 to 2000gp; more money than they should see for at least a couple of levels. Without this rule, it would be a choice between making 1st-level gunslingers go barehanded until they can afford a starting weapon, or allowing them to sell it the moment the game starts for far more money than they should rightfully have access to.
- Quite a far out example, but in Breath of Fire II, your town can be turned into a Floating Continent that can only be controlled by your father, who has been wired into the technology.
- In Mass Effect, Joker says something along these lines when asked about piloting the Normandy.
- Played very literally in the time between the second and third game. Joker and EDI (the second Normandy's AI) collude to give the impression that EDI is only a Virtual Intelligence that will respond only to Joker.
- In Jade Empire, Kang says the same for the Marvelous Dragonfly.
- Both of those expand the trope from just being about clunkers in the hands of someone used to their quirks, to extremely sophisticated devices in the hands of a specialist.
- And in Kang's case he spends literally every hour of the day making modifications to the Dragonfly (he doesn't sleep). The controls probably change completely from flight to flight.
- Both of those expand the trope from just being about clunkers in the hands of someone used to their quirks, to extremely sophisticated devices in the hands of a specialist.
- The Alteisen from Super Robot Wars Original Generation is an impractical junk heap of a Humongous Mecha that's very hard to handle due to its grossly encumbered frame, unbalanced weight, and ridiculous amount of thrust. Only Kyosuke is stated to be able to handle the machine within the story, thanks to his devil's luck. However, in gameplay, there's nothing that's stopping you from switching in any other pilot.
- The thing about the Alt and its upgrade is that piloting it is much like gambling. To use it effectively, the pilot has to dash in and hammer the enemy with close-to-mid-range weapons. The pilot can do a lot of damage this way, but it also leaves them wide open to enemy retaliation; it's a high-risk-high-reward style of fighting. Kyosuke, being The Gambler, likes to fight that way, and has the skill to pull it off.
- The heroes of Super Robot Wars Advance also have this going. Axel Almer and Lamia Loveless hail from the Shadow-Mirror universe, and they're pretty much the last remnants of the organization. Neither are science-types, so it's impossible to reverse-engineer their mechas (Axel's Soulgain, Lamia's Angelg, or the Vysaga, which can only be used by either of them). This isn't much of a problem since Axel and Lamia are Ace Pilots and the three aforementioned mechas are very well-suited for their purposes (brawling, sniping, and sword-fighting, respectively).
- In the mainstream SRW series, it's justified by most pilots being associated with a specific mecha, making it illogical for someone from another series to use them. On the other hand, Real Robot Genre series such as Gundam play with this - UC-era and Black History pilots are interchangeable, but AC (Gundam Wing), CE (Gundam SEED) and After War Gundam X characters are tied to their respective mechas.
- The third Dynasty Warriors: Gundam combines this with Mythology Gag. Any Mobile Suit with Attack Drones, psycommu systems, or is otherwise confirmed to require superhuman or extrasensory abilities to pilot can only be selected by pilots with the Newtype attribute* , even when the license to unlock it for everyone other than its signature pilot is obtained.
- In the original Ratchet & Clank, only Clank can start Ratchet's ship at the beginning of the game, since Ratchet is missing crucial components that makes it start. This aspect is almost immediately forgotten, until Clank reminds us of this after the first boss fight.
- Licia from Dark Souls II says this about a certain rotating door, saying she needs you to pay souls for her to perform a Miracle to operate it. She's scamming you: the device just requires a key, a key that she happened to find, and has nothing to do with Miracles at all. If you use the Crushed Eye Orb and kill her, you gain the key and are able to operate the mechanism yourself for free.
- The Last Hydral in The Last Federation is the only one who can control Hydral technology. Occasionally you'll find a battlefield where another race has managed to switch something on, but it's always berserk and attacking indiscriminately.
- Mr. Regular of Regular Car Reviews occasionally encounters a decidedly irregular car that requires special care and attention to operate properly. Footage of the owner explaining its quirks to him so he can actually drive it is often left in the main video, unedited, instead of being relegated to the usual POV video that goes up a few days later. Some notable examples:
- The Dodge Aspen, which is a shoddily built car that has aged poorly and has trouble turning over.
- The Ford Model T, which is one of the oldest cars in the world and was designed before people really knew what they were doing — the owner spends over three minutes trying to explain everything.
- A large part of the premise of Megas XLR is that Coop messed around with the mech's interfaces while refurbishing it, to the point that Kiva can no longer make heads or tails of it. Therefore he has to pilot it. The modified interface consists of a Plymouth Barracuda, several different game controllers, and many, many Plot Sensitive Buttons. Even Coop has trouble with it.
- In an episode of The Flintstones where Fred gets himself fired, Mr. Slate is forced to get him back after discovering that his handling of his dino-crane has made it so that only he can use it properly. Which makes sense since it's an animal—that he tamed.
- Certain high-end cars, such as Mercedes, tried this particularly those sold in countries prone to carjacking, sometimes offer thumbprint recognition as an ignition lock. Unfortunately, this just makes carjackers cut the driver's thumb off. Some thumbprint recognition devices also make sure the thumb is alive first (i.e. check for temperature and blood flow).
- In The Netherlands in September 2014, a monster truck accidentally drove into the audience. The police tried to reenact the tragedy, but was unable to get the truck started. According to the lawyer of the driver, it takes "a manual of two A4-sized pages" just to start the vehicle.
- Many highly modified and custom-built cars require specialist knowledge usually only possessed by the owner to be driven without blowing something up or in some cases just to start the engine. Most highly tuned cars will have an array of additional gauges on the dashboard displaying everything from boost and oil pressures to air fuel ratios, if these go too high or too low then a mechanical failure is more or less guarenteed. vehicles with race ignitions will often require a series of switches to be flipped in a certain order rather than just turning a key.
- On the other end of the spectrum, horrible jalopies often have chronic malfunctions, all of which are known only to their owners. If the carjacker does not know that one has to (for example) clean all spark plugs with sandpaper before starting the engine, he won't start it.
- In a non-automotive example, some televisions can be like this. If a person is used to the setup of one system, using someone else's can result in a lot of trial and error to watch something. Factor in DVD players or video game systems and things get further complicated.
- This can expand even further with one gamer's PC to another. Differences in PC configurations and peripherals can cause players to lose games against players with significantly inferior skills.
- Electronic devices can commonly fall into this. On the one hand, you have power users who customize everything they own, often removing things they don't need/use, altering settings in sometimes arcane ways, changing keybindings, and many other things that will make it a nightmare to use for anyone but them (sometimes this is done intentionally). On the other hand, you have generally incompetent users who perform no maintenance and exert little or no control over the device, making it difficult for even an expert user to undo the mess without a complete system reset. At the extreme ends, you have devices so heavily customized that even the original user forgets much of how to use it after an extended period away from it, and devices so mucked up by clueless owners that it's simpler to format them to solve whatever problems they have.
- Many pieces of software, particularly those created by independent developers have a tendency to become this making it nigh impossible to interpret or alter for anyone other than the creator(s). This also applies to old-school programming languages such as COBOL and FORTRAN, particularly when legacy hardware is being migrated to more modern platforms.