Pokémon/WMG/Type Matchups

Wild Mass Guessing specifically related to the Type Matchups in the Pokémon franchise. For other Pokémon related WMG's, see Pokémon/WMG.

Please add new entries to the bottom of the page.

Here's my our speculation about why certain Pokemon types are good against other types: Key (Flipped as necessary; all applicable signs used, separated by |): '+ > super effective against; -> not very effective against; #> Has no effect on.


 * Fire + >|<- Grass - Obviously, plants are quite flammable.
 * Have you ever tried to start a camp fire using green wood? It's very, very hard, trust me. Dead plants, sure, very easy, but if there's any green or life in it...
 * So the Theme Park Version of plants, i.e., "they're good in campfires" and "Only you can prevent forest fires"...
 * Go outside and find a green plant, pick it, and hold a lighter up to it. The fire will dry the plant out and make it flammable. The hotter the flame, the faster it'll dry out and the sooner it'll ignite.
 * The question here being if a healthy plant is really more flammable than any other living thing. Probably theme parked.
 * Probably just due to forest fires being the most common naturally occurring outbreaks of fires.
 * Water + >|<- Fire - Water puts out fire.
 * A caveat: It only makes flammable oils more angry.
 * Electric + > Water - Water conducts electricity.
 * Except for the part where that's false. Only water with conductive solutes conducts electricity.
 * Conductive solutes like electrolytes, which are necessary for most animals to absorb water with enough efficiency to survive? And of which sea creatures have much, and a tolerance for a greater amount than land creatures, due to living in the sea? If they Did Not Do the Research, and used the Clear, Cool, Theme Park Version of water.
 * Metal conducts electricity far better than water does, but Steel-types take neutral damage from Electric-type attacks.
 * Have you ever been in a metal cage near Tesla coils? The electricity stays in the outer edge of the metal, but if you put anything organic out of the cage, like say a finger, you will feel a painful shock. So that is why Electric is Neutral.
 * When has Pokemon ever been scientifically accurate?
 * When it was bug-catching back before the NES days.
 * steel types have metal on the outside of their bodies, not passing though their vital organs while water types entire bodies are conductive.
 * No electricity is felt inside a conductor. The damage is from the heat.
 * Or they just wanted to have steel take neutral damage from at least a few types, so they moved steel's disadvantage against electric to a resistance on electric's part. Water resists steel for the same reason (since water rusts metal).
 * Perhaps it's not that it conducts electricity. Electrolysis forms hydrogen and oxygen from water. The bubbles of H2 and O2 would decrease the amount of water (and Water types are probably very sensitive to that) and cause an increase in pressure (hydrogen and oxygen are gases in most conditions, and electrolysis of water basically turns two particles into three.) That could cause as much damage as the shock itself.
 * Deep Six explains why. Now You Know.
 * Also, in that Mythbusters episode about the "Electrified Bathtub" they showed that getting wet decreases your electrical resistance.
 * Grass + >|<- Water - Plants absorb water.
 * Of course, this brings up the question of why they're not constantly under the effects of Water Absorb or Storm Drain or have an immunity to it, however, this can be easily explained by the fact that while plants may absorb water, too much water can kill them. Still, plants are far more resilient to water than other materials.
 * Yes, too much water does kill them. Which is why they die if you repeatedly surf over them.
 * Fire + >|<- Ice - Fire melts ice.
 * A demonstration of why heat beats cold and not vice versa. Also note that while fire can melt ice, it is very difficult to put out a fire just by lowering its temperature. Fire suppression methods almost always try to separate the fuel and the oxidizer.
 * Also, wearing a fur coat in high temperatures is generally not a good idea.
 * Electric + >|<- Flying - Because lightning tends to strike objects that are high up.
 *  Ground + >|<# Electric - Did Not Do the Research, also dirt doesn't conduct electricity very well.
 * "Dirt doesn't conduct electricity very well" = Ground beats Electric. The problem being?
 * Or electricity could just bypass them and hit taller objects like trees or trainers.
 * The ground-type could actually be grounded with a conducting outer coat or body part, causing current to prefer that path instead of through vital organs (like the lightning rod of a building). As for why ground kills electric-types... dunno.
 * There are no "electric-types" in Real Life (except for eels, I guess), so grounding electricity is effectively the same thing as "killing" it.
 * Power Lines are sometimes taken out by earthquakes.
 * Case of Elemental Rock-Paper-Scissors: Ground has to be good for something, or no-one would ever want any ground Pokémon.
 * Ground is usually used to take out rock and steel types. But I suppose electric had to be weak to something. Though water seems to be a better choice.
 * Maybe Ground is good against Steel and Rocks since earthquakes, landslides, and the like can wreck stone and metal objects.
 * Psychic + >|<- Fighting - Standard Mage/Warrior match-up, and telekinesis stops physical attacks.
 * And since Fighting is based around martial arts, their moves are structured and easy to read and predict.
 * Plus they can pretty much pick up and toss the other pokemon with their mind alone. What they can't touch they can't punch.
 * Standard case of Mind Over Matter. Fighting types take a physical approach to lifting things, while a Psychic type can do so with their mind with little-to-no effort needed.
 * Fighting #> Ghost - Ghosts can turn intangible at will, so the attacks go straight through.
 * Normal #>|<# Ghost - Some sort of Anti-Magic power?
 * Or that the normal and spirit planes can't directly interact.
 * In the world of What You See Is What You Get, the blind man is a very lonely king.
 * So, why do Flying moves affect Ghost types?
 * They're being paid off by the Pidgeotto lobby.
 * It's the Air element behind Flying types that does the damage. Normal and Fighting are mostly just hitting a guy with raw physical power. A ghost can avoid that, but you can't out-maneuver the wind.
 * The ability Scrappy allows for Normal-type attacks to hit Ghost-types; therefore, it may be that the immunity comes from the Ghost-types scaring foes into disencouraging close combat. Remember the Silph Scope? Your Pokémon is probably not able to use it while you do, so, it's still fighting the scary, nondescript, and unidentified ghost you were seeing beforehand.
 * Maybe they just DON'T see dead people. Or ghost type pokemon.
 * Flying + >|<- Bug - Birds eat bugs.
 * The problem here, though, being that "Flying" is not just "birds"... I think it can get a better explanation than that.
 * Some bats also eat bugs. As do some flying bugs.
 * By that logic, Araidos beats all other Bug Pokemon.
 * And going by its unholy size, probably most Basic-stage Com Mons and Flying-types. Ever heard of the bird-eating spider?
 * I think for this it helps to understand that Flying-type used to be Bird-type.
 * The correct explanation is "Wind will blow away smaller things (like bugs) more easily."
 * Ground #> Flying - They're up in the air and therefore not affected, but Fridge Logic suggests some attacks should still hit.
 * Considering that some of the more popular ground moves (e.g. Magnitude) would be conveyed via the ground, this makes sense.
 * Moves like that club thing Cubone gets are probably quite slow, so a bird or wasp can fly rings around the strike.
 * You'd think that this would mean moves like Surf or Low Kick would be easy to dodge by flying just above it...
 * Also, Mud Bomb is a Ground-type move that Flying-types are immune to, but it's also a projectile that could very well be fired to hit a flying target.
 * Maybe the Mud Bomb (and other ground based projectile moves) simply have crappy aerodynamics.
 * Wouldn't that cause them to have trouble hitting anything? ...On second thought, that certainly explains their imperfect accuracy. It also explains why Earthquake is so accurate - unless you can fly, it's pretty tough to dodge an attack that's essentially just the ground shaking a lot.
 * Mud Bomb DOES have quite a bit of trouble hitting things with only 85 accuracy, so that suggests Nintendo might have thought of the 'crappy aerodynamics' thing. Most likely it's just gameplay/story segregation, it's easier to leave all ground moves as incapable of hitting fliers than it is to program certain moves to break that rule, and less confusing for the younger players I guess.
 * Rock + >|<- Flying - Birds have hollow bones, so hitting them with something hard can break their bones.
 * There is also the saying, "killing two birds with one stone"...
 * This can also have a far more convoluted explanation if you factor in that many Rock-type attacks could weigh the target down and force it onto the ground, which would only really be a problem for targets that aren't already stuck on the floor.
 * Heck, there seems to be a Rock-type attack debuting in Black and White which does precisely that.
 * Any more?
 * Steel ->|<+ Fire: Metal melts easier than a lot of the "hard" elements.
 * Metal also conducts heat very readily. One assumes their innards get cooked faster.
 * Grass <- Electricity: Plants have roots, so they're ground-like but not quite, I guess...?
 * Plants absorbs Water, which increases its conductivity.
 * Or it could be Wood is an insulator, and their exterior is probably wood-like, reducing shock.
 * This one was explained in the anime (sort of...), where Grass types can ground the electricity through some connection with the earth [that they rightly shouldn't have since none of them have roots.] Not as efficiently as a Ground type, but still.
 * That Bellsprout that pwned Godchu says hi.
 * Rubber is made from plants. You're welcome.
 * Synthetic rubber isn't necessarily.
 * Rock +> Bug: Go outside. Pick up a rock. Drop it on a nearby ant or slow-moving bug and see what happens.
 * That's mean... but so damn funny! *sniggers*
 * Fire +>|<- Bug: As any kid with a magnifying glass could tell you, bugs are notoriously easy to fry to a crisp.
 * Many parasites and biting bugs can be removed by fire or kept away by smoke too.
 * Dark ->|<+ Fighting: Dirty tricks fail against honorable warriors.
 * Three words, everyone: Cheaters Never Prosper. 'Nuff said.
 * Also, whatever was made to kill the former Game Breaker had to be weak to something itself -- why not the former underdog?
 * It's like punching an emo kid in the face.
 * One would almost think it would make more sense going the other way around. Dirty tricks take down Honor Before Reason, non-Combat Pragmatist warriors, but a sneak attack fails when the opponent can read your mind and toss you like a twig with the power of their thoughts. And yet most psychics are Glass Cannons, and will shatter if you look at them the wrong way.
 * I think there's a bit of Fridge Brilliance at work here. The strongest Dark attacks, Crunch and Dark Pulse, have a base power of 80 (though Payback and Assurance go to 100 in certain conditions), while the strongest Fighting moves are almost twice that strong. Obviously, a trained, honorable warrior has more power than a fighter that relies on cheating.
 * Actually, the strongest Dark-type move is now Trickery, with 95 base power. So... still nothing above 100. At least Ghost has Shadow Force.
 * Or maybe, cheaters anger honorable warriors to the point that they give the cheater types a bigger thrashing than usual. I think there's a trope name for that...
 * As well as an ability: the musketeer trio's "Justified" raises their attack power every time they get damaged by Dark-type moves.
 * I've always believed that it was because in Eastern Cultures, Martial Arts are used to "purify the soul, mind, and body", unlike in the west, where we view Martial Arts as merely for self-defense. Dark types have moves like "Snatch" and "Embargo", which are looked at as dishonorable, and thus "impure" tactics, making Dark moves (and Pokemon, by extension), less "moral". Thus, it's because of their clairvoyance and clean souls, and not necessarily their physical ability, that makes Dark types susceptible to Fighting moves.
 * You can also take Dark to a literal extent and think of fighters skilled enough to battle without seeing, i.e. blindfolded or in a dark battlefield.
 * But wouldn't fighters that can see in the dark have an advantage over those that can't? (Not so much when there's plenty of light, but when there isn't...)
 * Anyone who follows structured rules of combat such as in the martial arts that fighting types are based off of knows that not everyone follows these rules, so they would be prudent to learn to defend the vital targets a dirty fighter would go after while taking advantage of the shortcomings the opponent is trying to hide by employing these tactics.
 * Also, it's a bit tough to use crunch or bite when all your teeth have been knocked out.
 * Ice/Rock/Steel ->|<+ Fighting: The martial arts being used to break hard objects like bricks.
 * On a similar note, Steel +>|<- Ice/Rock: The sheer weight, mass, and density of metal is used to pulverize less sturdy hard materials.
 * It seems to be a power ranking. Steel is the strongest, then Rock, then Ice, but since Rock isn't as strong as Steel, Ice has normal effectiveness against it, and because Ice is the weakest, it gets regular damage from Normal type moves.
 * Makes sense, assuming normal people represent normal, you can usually break through a thin layer of ice and break it, when the same thickness of rock (and I don't mean those sissy gypsum rocks neither) or steel would support your weight.
 * Or let's just say that something akin to Moh's scale of hardness applies here.
 * On that same note, that might be why Normal -> Rock or Steel. Ever try hitting a boulder or chunk of iron with your bare hand? Ouch.
 * For that matter, the same deal goes with the rest of the Steel type's resistances. A being made of metal isn't gonna take much damage from rocks, plants, or dirty tricks. Steel might be too dense or heavy for Psychics to work their magic on. Water and Electric SHOULD be doing super-effective damage, but they do neutral damage for the sake of balance.
 * Psychic-type attacks failing against Steel-types can also be a result of failed attempts of any variety. Steel-types are usually the heaviest among Pokémon, so, they would be difficult to heft physically, let alone through mindpower. Also, the Steel-types' bodies are sturdy and probably hard to bend, which a Kadabra (for example) would probably try to do after successfully bending so many spoons, only to find that a Steel-type is no Spoony Bard.
 * I was thinking more on the lines on why Prof. X can't mind attack Magneto cause of his metal helmet. But Jean Grey could just lob stuff to hit him.
 * Psychic <+ Ghost: With greater spiritual awareness comes greater spiritual vulnerability.
 * Or maybe Psychics (representing the powers of the mind) are easily put off by things that inspire fear (Which Ghosts and other supernatural entities are good at.)
 * Or maybe Psychics are just susceptible to possession.
 * Water/Grass +> Rock/Ground and Ice +> Ground: Erosion.
 * OTOH, trying to kill a grass monster with fresh soil will only make it love you.
 * Dark +>|<# Psychic. Much like Ghost type, the malevolent thoughts from Dark Types overwhelm the overly sensitive minds of Psychic types. Alternatively, their moves are far harder to read, being improvised dirty fighting.
 * Much of the (decent) Fan Fiction describes dark-types as a psychic "void" of sorts. Assaulting one with psychic energy is literally like dumping water down a drain.
 * On that note, it's not hard to picture why Dark + > Ghosts too. One can imagine exactly what a walking energy-sucking void would do to a spirit composed entirely of energy.
 * ....So where does that leave Sableye and Spiritomb, then? If they're both a being of energy and a 'black hole' for energy....
 * Spiritomb looks kind of like a black hole.
 * I figured that the unpredictable Dark moves catch Ghosts off-guard before they can go intangible, which they usually would to evade Normal and Fighting moves. One should also consider that Ghosts rely on fear. Dark types are already pretty nasty and do not fear Ghosts, and can resist their moves as a result.
 * I always assumed that Dark-types knew things that Pokemon were not meant to know, and when a psychic type attacked them, they would Go Mad From the Revelation.
 * This troper believes that Dark types have such warped and twisted minds that anything a Psychic does to it is moot, considering that nothing shocks it anymore. Sort of like /b/ and the internet.
 * Whereas this troper theorizes that they have a "Dark Aura" which shuts down anything spiritual. Hence why creating a blast of said aura (Dark Pulse) is one of Dark's most powerful moves. Said aura creates a psychic shield, but physical blows simply ignore the aura. Since Dark relies on the Dark Aura for protection, it is vulnerable to something that ignores it.
 * In Marvel Comics, you know how The Hulk's mind is too chaotic for psychics to breach? Same idea in this matchup. The Psychics can't "see" the Dark types' minds because they're clouded with evil. So they can't make a mental connection. Hence, Miracle Eye, which works like Psychic night-vision goggles.
 * Since psychic-types are based on the mind, maybe psychic's weaknesses (ghost, bug, and dark) are based off three common fears?
 * Which begs the question, why aren't they weak against the Flying-type (fear of heights)?
 * The Dev Team Didn't Think Of Everything.
 * Alternatively, they don't fear heights due to their Telekinetic abilities.
 * This troper thinks that Psychics used the dark power of Ghosts for their attacks. These spirits could corrupt them, but they could also hold their own against them. But the spirits are just a part of the power of Dark that is all that the Psychics have.
 * Psychic powers target a Pokémon's soul. Dark Pokémon don't have a soul at all.
 * Then they shouldn't be able to gain any tameness or befriend anyone, a la Nobodies. Also, look at adorable Zorua and tell me it has no soul.
 * Psychic types have highly developed minds which generate their psychic energy and distribute it along equally advanced nervous systems; this leaves them highly sensitive to physical pain, hence their glass cannony-ness, vulnerability to dark types who hit below the belt and similarly target sweet spots as well as the painful bites and stings of bug types, though fighting types which make more direct attacks to vital organs can be defended against through mind over matter. While psychic types trying to damage dark types are like a candle trying to light its own shadow.
 * Mundane theory. Dark types are evil and crafty. They know how to lie, fool, and hide from psychics and throw off their defensive strategies. The "psychic void" thing falls apart when you realize they're only immune to damaging psychic moves. Imprison and Future Sight still work and they have no defense against Mind Reader, probably because it's normal and thus too straight-forward to deceive.
 * Guys... a reminder that Dark Is Not Evil needs to be thrown in here. Dark, ghost, psychic, and fighting (ki) are the "spiritual" types. Given moves like dark pulse, shadow ball, psybeam, and focus blast, mundane explanations may not work too well anyway.
 * Thank you for reminding everyone about that! But technically, they are crafty, so maybe they think "I'm going to use bite!" when the Psychic pokemon reads their mind, but it turns out that the Dark type does something completely different that the Psychic wasn't expecting.
 * Mundane take 2. Anger, malice and resentment are commonly sighted as a "negative" emotions, which dark pulse is made of. However, peaceful protestors can be motivated by anger at injustice, the wrongly oppressed will resent their treatment and reformers have malicious intent against the current order. As long as Wrath is suppressed there is nothing wrong with those thoughts, Dark Is Not Evil. Absol warns people, Umbreon grows with love but they still get their power from anger, malice and resentment. Make a fist and think evil thoughts, it feels good. Someone zealously motivated in such away will be hard to reason with. Their minds are still detectable(future sight/imprison/mind reader) but their zeal blocks out psychic influence. Shaming the Mob proves they can still be reached. Miracle eye allows psychics to see what makes them tick then undermines their motives.
 * Dragon <+> Dragon: Dragonhide can only be pierced by a dragon's fang/dragonfire, much like many stories with dragons in them.
 * Poison +>|<- Grass: Plants are sensitive to pollution.
 * Weed killer. Which makes it rather annoying that Bugs are no longer weak to poison as of Generation II...
 * Simple. They adapted to poisons just like real bugs do.
 * Ghost/Fighting <- Poison: Whether through rigorous training to improve metabolism or lacking any meaningful metabolism at all, poison doesn't affect these types too much.
 * Actually, Fighting <-> Poison: the idea is that intensely physical fighting techniques don't do much to destroy the poison itself (see below).
 * Steel <# Poison: Just how would you go about "poisoning" a hunk of metal? Alternatively, they're too hard and airtight for the stingers/pincers/sludge to penetrate their outer defenses, which would at least explain why Rock-types don't benefit from the same immunity.
 * I always assumed most steel types were either inorganic (Thus can't be poisoned in that respect) or just covered with a more or less airtight impenetrable shell. Don't ask about Lucario...
 * Rock types do seem to be portrayed as more organic (strangely) though you do occasionally hear a story about a creature of living rock, certainly more often than one of living steel. The only time you hear about poisoned steel, the steel is just coated in poison and is itself unaffected, being used to deliver the poison. Metal has also been used to store and transport poisons and acids, before glass. Then there is the fact that some metals are themselves poisonous, hence heavy metal poisoning. So take your pick as to why they are immune, there are plenty of reasons.
 * Lucario's Steel typing never made any sense anyway.
 * Rule of Cool, man.
 * Actually, I've always thought either: A) His training in the martial arts is so far beyond that of any other fighting-type that he has honed his skill to machine-like precision. B) His fur is just that strong and dense. C) Both
 * I like the idea that instead of fat under his skin, he has steel plating.
 * So then how the hell does he move? Actually, that explains his merely so-so Speed...
 * Psychic +> Poison: Psychic healing/purification. Sure, it's dubious in real life, but all those other psychic powers clearly exist in the Pokemon universe(s), so why not?
 * I always looked at it like "Mind can overcome corruption, but only brute force can overcome evil" for Psychic, Poison, Fighting, and Dark. Hammy and lame, yes, but...
 * Also, anything can be deadly as long as it's in the right (or wrong) place, especially poison. Psychic-type attacks have been shown to be capable of moving the target's entire body around, so, it shouldn't be hard to relocate a Poison-type's toxins to places where they're not as convenient as they are in their venom sacs.
 * Alternatively, some psychic attacks work by overloading the foe's brain, like Extrasensory. Most real creatures with poison have some defense mechanism against self-poisoning, like snake fangs folding in when they close their mouths to avoid stabbing themselves. Maybe Psychic-type attacks override those defenses.
 * I had always thought it was something like how Psychics don't need to come into contact with the Poison material, and thus aren't poisoned on contact, because they don't touch it. The reason that it's only not-very-effective instead of inneffective is because when the poison creature actively lashes out, it still makes contact.
 * Ice +> Grass: Plants can be killed by sudden frost almost as easily as fire.
 * Many plants go dormant during the winter... which suggests evergreens would be part fire?
 * Or part ice? Anyway, a dormant grass-type would effectively be in hibernation, which is not conducive to fighting other Pokemon.
 * Bug + > Psychic: This Troper actually heard of a theory once that the psychics' strength is proportional to their state of mind. So they can beat up the big, tough bully because they're confident they can do it, but they're weak to fear, the worst of which would be irrational fears, some of which are bugs, the dark, and ghosts, which could be a reason why they're weak to those types.
 * Alternatively, bugs pour into skulls and feed off of psychic brain tissue, because psychic skulls are porous to other psychic powers to escape their mind to be used.
 * Well, the reason bugs do extra damage to psychics: if you've ever been in a fly-heavy area, you'll know it's hard to concentrate and the little buggers are everywhere. A Psychic has to have total control at all times, or it risks some form of psychic blowback. The extra damage from Twineedle isn't so much to do with the needle but due to the backlash.
 * Right. Bug type moves center around being annoying. Biting, shining bright lights in the eyes (Signal Beam), making lots of noise (Bug Buzz), or just darting around. The average Psychic type is psychologically sensitive (being Psychic and all) and can't deal with such torment.
 * Since psychic-types are based on the mind, maybe psychic's weaknesses (ghost, bug, and dark) are based off three common fears?
 * Or maybe the Bug-type minds are either too simple or too complex (Hivemind or something similar) for the Psychic-type to safely affect?
 * Bug-types don't resist Psychic-types. But maybe the hive-mind thing could explain the weakness... something about the Psychics not being able to read their thoughts, and therefore never see their attacks coming?
 * Except the only bug Pokemon that could be called hive minded is Combee. More likely psychics are too bugged to focus their defenses.
 * Flying + >|<- Fighting/Grass: Due to fliers coming from above, it makes it much more challenging for the fighter to anticipate or evade its attacks. As for grass, the wind blows leaves off trees.
 * I dare you to try to Karate Chop a bat in real life. And as for plants, they're sort of more flexible. Maybe not trees, but actual grasses can often bend quite far and not break or die. Unlike, say bones.
 * Also, birds eat plants, and most Fighting-types can't fly or use projectile attacks, so Flying-types can avoid them.
 * And no matter how hard you try, you can't block or dodge wind with your bare hands.
 * Flying types beat grass because grass is made up of plants and mushrooms. Flying types get high but lose to rock because it's not good to fly stoned
 * Ice + > Flying: Ice can freeze the Flying-type's wings in mid-air, causing it to come plummeting down.
 * Also, many species of birds fly south for the winter, presumably because they have low tolerance for cold.
 * Additionally, ice can cause wings of aircraft to become less aerodynamic and stop producing lift. Not sure how well this carries over to living creatures, but still...
 * Flying Pokemon haven't solved the icing problem. Except for Articuno.
 * Birds use columns of warm air (called thermals) to help them travel without having to flap (just spread your wings and up you go). Since ice-types would probably be pretty cold, they'd cool the air around them, making flying-types have to work harder to stay in the air. Thank you K.A. Applegate.
 * Ice + > Dragon: Dragons are reptilian. Reptiles are cold-blooded and thus don't function well in the cold. Alternatively, Dinosaurs Are Dragons, and one of the many theories explaining the dinosaurs' extinction was that they couldn't adapt to colder global temperatures.
 * Yet they're resistant to fire...
 * It's quite common in mythology that dragons are immune to or, by association with Salamanders, absorb fire (except sometimes dragonfire).
 * Thus dragon's weakness to itself.
 * This troper's theory is that Dragons are ancient creatures associated with climate (especially in Asian mythology; and that's a reason why they're resistant to important elements in the game: Fire, Water, Electric, Grass) and what they may fear is a return to an Ice Age.
 * In one of the games, a Dragon Trainer mentions how Dragons are "Full of life energy". How do you put a damper on life energy? Give it a big chill. Lowering the body temperature of something high on life energy would decrease the flow.
 * Especially since cold is basically an energetic void, so the cold could be drawing their life energy out (much like how it draws out heat energy).
 * Poison <- Fighting: Some of them are gelatinous blobs, living stomachs and gas clouds, and others are things like snakes, which unless you crush them under a rock or cut them in half, can really take a beating.
 * Ground + >|<- Poison: Certain types of clay can neutralize poisons.
 * Bug <-> Fighting: Fighting types have fast enough reflexes to fend off the worst of a bug's sting, but due to the size of a bug poke, its exoskeleton is too thick for mundane kicks and punches to do anything too severe to it.
 * Or consider the way many bugs swarm and dart about erratically.
 * Again, go out and try to karate chop an ant or a fly.
 * Bug-type moves center around being annoying/creepy (hence Psychic's weakness to them). Fighting types are too hardassed to be phased.
 * I was trained to be able to defeat any man. Man-spider, fine. Arachna-dude, fine. Plain or GIANT spiders, no chance. I mean, do YOU know a spider's pressure points? 'Cause I sure don't. Do they HAVE pressure points? I wouldn't know.
 * Bug -> Ghost: Ghosts are masters of harassment and mind games. Insects are annoying, but can't measure up.
 * Bug -> Poison: Even though bugs adapt to poisons, it still takes time. Time which Poison types will not give them.
 * Bug + > Dark: On the obvious side of things, fireflies can light up the dark.
 * Sneaky tricks and attacks are very difficult to pull off on creatures who have too simple/alien a thought process to fall for them. They would probably just go through with the offensive anyway. Same thing if the attacker is a product of a Hive Mind.
 * Kamen Rider thing? Good is based off of an insect.
 * Yeah, "Good vs. Evil" again. Fighting types just punch the Dark types until they run crying. But Bug types look outclassed, don't they? How do good guys usually beat villains that outclass them? They harass them until they're worn down and vulnerable. That is... they Bug them.
 * Dark and psychic could have their focus thrown off by being bugged since both of them are mental to a degree.
 * Bug + >|<- Grass: simple; bugs eat plants.
 * Fighting + > Normal: How would you feel if a Professional MMA fighter punched you in the face?
 * Alternatively, a trained fighter should easily beat a normal person in a fight.
 * Ground +> Fire: Shoveling dirt on an open flame, even oil/gas or electrical ones will put it out, while using water to put out a B or C type fire... not so much.
 * Ground -> Bug: A lot of bugs live in the ground, so it would be kind of like attacking a fish with water.
 * Psychic -> Steel: Know that flesh cannot mark steel. Know that steel may mark flesh [...] Know that the tentacled ones were of flesh. They relied on the flesh and used it as tools for their will, well that and steel was introduced to curb psychic's curb stompyness.
 * There's a psionic defense in original AD&D called "Tower of Iron Will".
 * Perhaps psychic types work by altering the currents in the brain with some sort of weak but precise electromagnetism, which is messed up by trying to work through metal? Kind of like Magneto's psychic-proof metal helmet.
 * Or regular tin foil caps.
 * Dark - > Steel: Once you get past the cruelty of them, Dark type moves aren't very strong. Consider that other types have moves boasting 150+ Base Power, while Dark struggles to reach 95. Steel just hangs tough.
 * Alternately, steel types are just Made of Iron, and resist everything that doesn't have a particular reason to be strong against them.
 * Fighting->|<+Flying Did you ever try to punch a bird? Conversely, a bird could last longer against a trained fighter than a normal person.
 * Grass +> Rock Now call me crazy, but I think this matchup is actually a reference to literal rock-paper-scissors. Grass type is basically "Plant" type, which would include wood and other cellulose-containing compounds. In other words, the kind of materials paper is made of. And paper covers rock.
 * Plants can cause some forms of physical erosion. The roots get into cracks that are in the rock, and as the roots grow thicker or bigger, they cause the cracks to become wider and split the rocks into smaller pieces. Also, I don't recall the exact length, but I recall there was a Douglas Fir tree that had a tap root push its way through over several hundred miles of solid rock to find water....
 * Wait a minute, if Rock is weak against Grass because of that, then shouldn't it be weak against Ice too? Water gets into a crack and freezes, causing it to expand, widening the crack and eventually breaking the rock. Of course, Rock has enough weaknesses as it is.
 * Wood based weapons tend to be superior to stone ones.
 * What is this I don't even... How are wooden weapons superior? Other than being lighter and possibly easier or quicker to make, I just can't understand how you even arrived at that conclusion.
 * How, besides being lighter and easier to make? Stone may be harder, but shaping it to a sharp point makes it much more brittle, so the debarked wood equivalent will last longer, meaning your forces suddenly have more spears and arrows than the other guy just using rocks.
 * Also, bamboo shoots can go straight through rock.
 * Ghost ->|<+ Dark Ghost types are only KINDA evil; they scare people, but only to stay alive. Dark types are just rotten to the core; to them, Ghost tactics are just love taps. And in battles between two guys who use the same power, but one is way better at it, who ends up worse for wear?
 * Or maybe Ghost-types are minions of Dark-types.
 * Again, Dark Is Not Evil. However, death is associated with darkness, and ghost stories are often associated with dark places like haunted houses, mines, tunnels, and graveyards. Thus, ghosts could be considered to hide in the dark. Dark types, of course, can see just fine in the dark, so ghosts can't surprise or evade them.
 * Have you ever tried to scare an emo? They just end up insulting/ humiliating you.
 * Ground +> Steel Soil can erode and dull metals to the point where they are no longer useful. For example, drag a knife along a dirt road and it will become blunted.
 * Ghost <+> Ghost Maybe ghost types exist on a separate plane and are much weaker than other types, but resist everything, so when they seem to be taking full damage it's only half damage on their weaker forms, but Ghost inflicts full damage to itself.

Chapters 4-9 of this fic give pretty awesome explanations for every type and type match-up!