Selective Magnetism

""Magnets only do what they need to do for the purposes of the plot. That's what X-Men taught me.""

- A Let's Play of Beyond Good and Evil

""It's the law of Selective Magnetism, it only works when things look cool or funny. [...]"

"Okay: the flashlight, the knife... I guess magnetism only works if you believe in it."

"Like Tinkerbell.""

- Kevin Murphy & Mike Nelson, Riff Trax of Indiana Jones and the Kingdom of the Crystal Skull.

Powerful magnets are cool. Generally, it's a lot easier in cartoons and TV shows to create a magnet that is powerful enough to rip the gun out of your hands than it is in real life. But the real catcher isn't how much it attracts, but what it attracts. And, by extension, what it doesn't attract.

Often magnets are selective about what they attract, only pulling in the obviously metal stuff, while ignoring other items that should be attracted. Or else pulling things in one at a time, instead of everything at once.

Can be Truth in Television, as only three common metals are ferromagnetic: iron, nickel, and cobalt. Metals like gold, aluminium, and others, despite being slightly responsive to magnetic fields (a property known as paramagnetism), are by and large not affected by magnets. Writers are often unaware of that fact.

The iron in human blood is locked up in molecules, and thus no longer ferromagnetic: no dice there. Water has a molecular dipole, where one end of the molecule is slightly negative and the other is slightly positive, to the point where a really strong field can levitate a frog. But no one ever considers that aspect, either.

A subtrope of You Fail Physics Forever unless it's an explicit superpower.

Anime and Manga

 * Kinnikuman. Dream Tag Tournament's tag team of Neptuneman and Big the Budo and their spammy Magnet Power. More powerful displays DO attract any and all nearby metal... but they all seem to go towards the designated target, rather than the origin, there the force is at its strongest.
 * Eustass "Captain" Kid of One Piece has this as his Devil Fruit power. Thus far his powers seem limited to the basic 'attract' or 'repel' rather than full-on metal telekinesis ala Magneto.
 * There's also Campachino and Brindo, who can attract and repel each other.
 * In Jojo, during the Stands arc, one of the villains has a stand that makes people magnetic. This has no ill effect on his own (it should, as magnetism is not exactly healthy), but attracts metallic objects at a fastly growing rate. To make thinks more dire, two different protagonist are charged with opposite poles, so they are strongly attracted each the other. While it's mostly realistic, somehow the protagonists are able to attract objects way heavier that themselves, instead of being attracted
 * In Naruto there is Magnet Release used by The Third and Fourth Kazekage, and Kumo ninja Toroi. The magnetism works by converting chakra and magnetizing whatever you want. The Kazekage fight by turning Iron Sand and Gold Dust (respectively) magnetic and showering enemies with it. Toroi turns enemies magnetic and throws metal objects at them.
 * A filler villain had the ability to turn himself magnetic at will. Hinata defeated him by forcing to turn himself magnetic and pushing him off a cliff into a pit full of iron sand, where he was Buried Alive by his own power.

Comic Books

 * Magneto. Scientists also promptly said his powers wouldn't work that well due to the Third Law of Motion - to every action there is an equal and opposite reaction, thus while lifting a battleship weighting tens of thousands of tons the mutant would also be attracted to it like a fridge magnet...
 * Which is a preposterous statement. Unless he is flying directly over the battleship, it is clear that not he himself is magnetic, just something in the direction the battleship is moving in. If that something can only be air, there should be extreme winds like never seen before on earth, but he himself should be fine. Unless he is somehow holding the magnetic medium in place, then it should drive him right through the earths crust...
 * Since his power appears to extend to nonferromagnetic metals, I'd say that most likely it'd drive him straight into the ground.
 * Justified (somewhat) in some stories written by the less scientifically illiterate among the writers, in that he uses his control over gravity to "anchor" himself into position relative to Earth. The reaction force is transferred to the planet's own mass. Of course, the transfer of momentum as such should still crush him to a pulp, so he must be tougher than he looks ...
 * At various times it has been stated that Magneto is not personally magnetic so much as he manipulates the Earth's planetary magnetic field. Thus this sort of thing would not be a problem, since any motion effects would be against the mass of the Earth, not Magneto himself. However, Magneto has also been shown as being able to use his powers in places such as other dimensions like Belasco's Limbo, where one is left wondering as to the source of the magnetic field he is manipulating.
 * This was RetConned to include all metals. Magneto could fiddle around with virtually all electromagnetic effects, too. Up to and including functional telepathy, in the hands of some writers.
 * His 'telepathy' was described as controlling minds via the iron in the blood of the victim's brain. He also has strong concentration and iron will to Charles Atlas Superpower-level (hence a few odd instances of astral projection. And in the comics, it's not his helmet that protects him from telepathy -- it's being just that bullheaded.)
 * The mental powers were Early Installment Weirdness - astral projection and mind control were the results of his 'powerful mutant brain' back in 1963. When it comes to canon, Marvel isn't DC - if it happened, it happened, even after you've rethought. Hand Wave time! Past instances of mind control became 'manipulation of the iron in the blood of your brain.' Astral projection is a bit harder.
 * Since then it was described that Mageneto always had minor telepathic powers as secondary abilities separate from his control over magnetism, though nowhere near as powerful as Professor X's. In the X-men vs avengers he uses a special helmet that enhances those abilities.
 * Mostly, the writers use Mags' powers as 'telekinetically controls metal objects' these days. Laws of physics need not apply, particularly with regard to reaction force.
 * In Ultimatum Magneto is seen using "magnetism" to stop his arm from bleeding.
 * Likewise, it's never been clear whether the powers of Polaris (Magneto's daughter), are derived from her physically or whether they are psionic.
 * In the Young Avengers mini-series The Children's Crusade, Quicksilver tries to kill his father by hurling some wooden fence posts at super-speed. It is made to appear as though this is a credible threat, even though it would raise the question of why nobody ever thought of using wood as a means of harming, incapacitating or imprisoning Magneto before.
 * Really, the perfect sum-up: "I've always thought that Magento's poweres (sic) weren't "Control over magnetism" but "he can do anything as long as he mentions magnetism while doing it"."
 * Goldstar has this in addition to all of her brother's powers.

Film

 * In the X-Men film series Magneto does rip iron out of someone's blood, but it was pure, unabsorbed iron, injected into his bloodstream the night before by Mystique. Whether it's possible to do that and have the dupe survive is another matter entirely, but hey, they tried.
 * The film also went to the trouble of making the guard look extremely unwell when he arrived for his shift in the facility where Magneto was being held, though whether he was suffering from incipient metal poisoning or merely very hung over wasn't spelled out..
 * The movie series Magneto does not share his comic book version's ability to create force fields. In the comics this power often rationalizes why Magneto can resist virtually any form of harm as well as affect things that should not be noticeably affected by magnetism otherwise. Which was presumably why he could not burst out of a plastic prison cell.
 * In Indiana Jones and the Kingdom of the Crystal Skull, Indy uses gunpowder to find where a magnetic box is in the warehouse. The gunpowder easily flies across the entire warehouse, but other magnetically charged items don't even begin to be attracted to it unless they are literally within feet of it.
 * Although it later turns out the skull doesn't have regular magnetic properties, and can attract metals like gold. Which is explicitly pointed out by Indy as being strange, so at least the writers did some research.
 * On the other hand, gunpowder isn't magnetic. As a mixture of charcoal, sulphur and potassium nitrate, it isn't even metallic. Okay I guess it looks a bit like iron filings...
 * Charcoal + sulfur + saltpeter is black powder, which hasn't been used except in fireworks and niche applications since the end of the 19th century. Not that it matters much, since none of the smokeless powders that replaced it are magnetic either.
 * The movie was downright silly with this. In one scene, it affected the ceiling lights hanging down, but it never once affects the jeep they use to drive around in. Also, The Dragon can swing her sword around all she likes, but the magnet only affects it when it becomes dramatic. Everybody can carry guns around the skull without being hindered.
 * The Selective Magnetism done on purpose and was meant to imply the otherworldliness of the skull. However it apparently failed to clearly express this.
 * Even after the skull attracts some gold coins and Mutt flat out says "Gold isn't magnetic" and Indy follows up with "neither is crystal"? How much clearer did they need to be?
 * Apparently, the magnetism is also selective in terms of plot progression. The ceiling lights weren't affected by the box until after the box was discovered.
 * Some people have noticed that Jazz in the Transformers movie was able to rip guns out of the hands of Sector Seven agents with magnetism, but their cell phones still worked. But then, Advanced living machine Alien technology may justify that.
 * A magnetic field is something different than an EMP. And i doubt that a field just strong enough to rip weapons out of their hands would induce enough current to fry their phones that way, as it isn't pulsed quite that fast.
 * Terminator III had John Conner use a magenetic coil against the Terminatrix, which dragged the gun out of his hand, but they seemed unaffected by anything else on their bodies, like belt buckles or zippers. It might work, however, if they're made of non-ferromagnetic metals, such as brass or aluminium.
 * In This Island Earth Exeter tells Cal and Ruth their hands become stuck to metal supports because the supports are magnetized. When the film was shown in Mystery Science Theater 3000 The Movie, Mike noted "if your hands were metal that would mean something."
 * The second Spider-Man film boasts a fusion reactor that attracts anything even remotely metallic to it (from up to several hundred yards away)... except for the components of the reactor itself, Doc Ock's tentacles, and little things like the metal components used to hold the pier together... Granted, Ock does mention that the tentacles are 'impervious to magnetism'...
 * In the James Bond film Die Another Day, Bond activates an MRI machine to disarm a North Korean soldier. Ignoring the fact that it takes hours for an MRI to fully power up, the only things that the magnet attracts are the pistol and a few medical implements, leaving the steel table, hospital bed, etc completely untouched.
 * Typically the magnet is always on, and the gun was only affected when it was held relatively close to the magnet; the table and hospital bed were probably heavy enough not to be affected noticeably. Doesn't really explain why the medical tools -some of them quite sharp- were allowed in there in the first place, however.
 * The titular hero from The Return of Captain Invincible has this power, but he hasn't used it for decades and it seldom works as intended.
 * Justified as an actual clue in The Raven (2012), in which Fields discovers that a hair from a crime scene is strangely attracted to a magnet.

Literature

 * In the Charlie Bone series by Jenny Nimmo, there is a boy named Joshua Tilpin who is a living magnet. Except that his magnetism attracts things from dust bunnies to paper to non-ferromagnetic materials. It also extends to his personal charisma, making people just instinctively like him even though he's an immoral brat and one of the bad guys. Interestingly enough, the only thing he's seen not attracting is metal.

Live Action TV
"Foreman: Standard police-issue Kevlar vests don't have the ceramic plate inserts that would shatter a bullet. They would just catch it, which means Baby Shoes was using .38 caliber hollowpoints, which, unfortunately, are ferromagnetic. House: It's so cool that you know that."
 * In Jack of All Trades, to stop an execution, Jack turns the Governor's armor into a powerful magnet, literally pulling the bullets out of the air and sticking them to his armor. The guns, everybody's jewelry, buckles, etc, are all left perfectly still. Swords are not attracted to the armor until they are drawn.
 * Myth Busters tested a MRI machine affecting metal fragments in tattoo ink. While it was very attracted to the metal block they used for a test, the machine didn't seem to affect the ink.
 * Except the (iron-based) black ink.
 * This was done in an episode of House, too. As well as House blowing up the MRI by shooting a corpse in the head and sticking the body in to simulate a patient with a similar injury, testing whether or not the fragments were large enough to be ripped out (more than enough.) House said it was cool that Foreman knew the fragments were ferromagnetic.


 * In another episode, a magician forgot about the key he had swallowed. When he got his MRI, it ripped through his intestine.
 * The rifts in Primeval, which produce a strong magnetic force when the writers remember that they do. Doesn't affect technology (they send a robot through at one point.) Just occasionally attracts things.
 * And the things that get pulled in by the magnetic field are just gone, they don't appear on the other side or fall down when the anomaly collapses.
 * Of course, if they did go through to the other side, then they'd have to explain why a modern-day metallic object was found among dinosaur fossils dating back to that time period.
 * In Lost, where Sayid is shown pounding away on a concrete wall with a metal strut. Jack wanders by and demonstrates that whatever is behind the wall is extremely magnetic, to which Sayid responds that he is glad the strut is made of titanium, which has very little magnetic attraction to the wall
 * In the fifth season, a man is killed when said magnetic field rips a filling out of his mouth, though fillings usually don't have ferromagnetic metals. However, this may be intentional by the writers, to emphasize that the pull was sudden and strong enough to have this effect.
 * In Fringe an MRI manages to attract an iridium compound out of someone's brain. Never mind that a) iridium is not (ferro)magnetic and b) metallic compounds have no free-flowing electrons to facilitate a magnetic field. If we then assume these are positive iridium ions in solution, just to make something attracted to the magnet, it would behave like all the other ions in your bloodstream and do naff all, certainly not making your blood vessels stand out from your face.
 * Similar to the Fringe example, Hodgins on Bones once searched through a planter with magnetic gloves to find a titanium bone implant from the Body of the Week. Titanium isn't ferromagnetic either, which Hodgins should have known given his chemistry training.

Other

 * There's a story about a boy who became fascinated with magnets after seeing them work in his science class at school, so he decides to steal the teacher's magnet and place it in his pocket, on his way home, first he attracts a metallic can of cigarettes which becomes magnetized and starts attracting other consecutively larger objects, soon he attracts a train and a space probe from orbit (astronaut included).
 * The Magnetism element in Bionicle.
 * An ad campaign once featured a boy discussing his new invention: the Lost Cat Magnet. Exactly What It Says on the Tin.

Video Games

 * Referenced in Simon the Sorcerer, where
 * Perhaps the worse example of selective magnetism is in The Legend of Zelda: Oracle of Seasons, where you get magnetic gloves that not only exclusively work on only things labelled with an "S" or an "N" - which come in four forms: spinny things labelled S, cylinders sticking out of the ground labelled S - both of which pull you to or push you away from them - and balls labelled N, and enemies that flip between S and N which you can move. Whether you push or pull these magnetic devices depends on whether you set the gloves to north or south poles, and they work on nothing that's not explicitly labelled as a magnetic monopole. Magnetic monopoles have never been discovered in real life, real magnets have both a south and north pole, not just one or the other.
 * Also, it only works with the one monopole directly in front of you. Even if there is a magnetic monopole closer to you but slightly off.
 * In The Legend of Zelda: Twilight Princess, there are large sections of magnetic wall and ceiling Link can stick to with the iron boots. Keep in mind that Link runs around with a large metal shield on his back. Though the shield could be a non ferromagnetic metal.
 * And this webcomic page takes it to the other extreme, with magnets attracting a book, an Oocco...
 * And played with in the NES version of Mission Impossible. One room is just filled with these, and they affect ONLY weapons. Those lead-core bullets and wooden boomerangs get pulled off-track and into them, which is obviously a pain (or a perverse joy, if you like watching enemy bullets never get farther than two pixels from their guns). Weirdly, while it affects outgoing boomerangs, returning boomerangs fly straight and true.
 * Command & Conquer Command & Conquer: Red Alert 3 has the Soviets using various magnetic weapons: from magnetic harpoons to magnetic weapons that strip armor and weapons off enemy vehicles to magnets that suck units into SPACE.

Western Animation

 * Dr. Polaris in Justice League Unlimited. Though technically he describes his abilities as "ferro-kinetic", so it may just be really specialized telekinesis, except he's defeated by the logic that a magnet loses its charge when heated up enough, which given that he was fighting someone who's Playing with Fire, may just be a case of When All You Have Is a Hammer.
 * In addition to the comic examples given above, Magneto in the X-Men animated series brought down a brick wall by magnetising it, used a magnetic forcefield to deflect Cyclops' Eye Beams, and levitated Storm and Cyclops with similar forcefields - and that was just in his debut story.
 * Of course, Mags' levitation powers were described in the comics as 'cutting across the gravimetric lines of force,' which seems to mean "gravity=magnetism," and he's actually de-gravitizing them (and himself, when he flies.)
 * Clearly Magneto's powers are a clue to the discovery the Theory of Everything in that universe. On a side note, I wonder if Magneto's ever been shown to use the electro- part of electromegnetism in any versions.
 * An old Bugs Bunny cartoon, Compressed Hare, gets this one right to utterly hilarious effect. Wile E. Coyote, having given Bugs an iron carrot, thinking the rabbit will actually eat it, activates a ten trillion volt electromagnet to attract the carrot (and thus, Bugs) to him. It works: the magnet draws the carrot. And then Bugs' mailbox, all the metal appliances in his home, then a stop sign, a great deal of barbed wire, various large vehicles, satellites out of orbit and finally, a rocket attempting to take off...
 * In the classic Road Runner shorts, Wile E. would often try a scheme to get the Road Runner to eat iron-laced birdseed, and then use a magnet to attract the bird to him. Only for the magnet to improbably attract something else made of iron (A canister of TNT, with the fuse already lit) or attract him to something metal nearby (train tracks, just ahead of a train). At least it was always something that would be magnetic.
 * In Ben 10 Alien Force the alien Lodestar, who uses magnetic powers, tried to use his powers to take the guns of some warlike aliens. He ended up attracting all their guns, but fortunately didn't pin himself to any of their tanks - or have their tanks come flying towards him.
 * Agent Six in Generator Rex can combine his swords to get this.
 * Megavolt has fun with this in a Darkwing Duck episode. Somewhat justified, since his goal is to attract..things you can build a BIGGER magnet with. Which he'll use to steal ... more magnet parts. The #3 most dangerous criminal in Saint Canard isn't known for his sanity.
 * A recent episode of SpongeBob SquarePants featured Mr. Krabs abusing Gary's new "ability" to attract coins, and ONLY COINS. Gary can even get coins out of change machines and parking meters. And why is it Gary can do this? He swallowed a fridge magnet!
 * Referenced in Phineas and Ferb The Movie: Across the 2nd Dimension, where an electromagnet is described as being very powerful, so powerful it even attracts aluminum.
 * This may also be a subtle effort to Retcon a flaw from the pilot episode and Rollercoaster: The Musical. In both of these, tin foil (which is generally aluminum) was attracted to a powerful magnet of Doof's in his effort to "Pull the eastern sea-board in a westernly direction".
 * A comedic series can be forgiven for, well not taking itself too seriously, but Inspector Gadget went rather beyond most examples of this trope when the Mad Scientist Big Bad of an episode pursued the rather straightforward plan of stealing all the world's gold - including pulling fillings out of peoples' mouths - by attracting it to his "gold magnet". Which was only about the size of a car.