After generations of {{Kaiju}} movies including Franchise/{{Godzilla}}, Franchise/{{Gamera}} and countless imitators, viewers seem conditioned to accept that any giant monster or robot is completely [[ImmuneToBullets immune to conventional weaponry]]. This can be a problem for filmmakers, either making the military in their films look stupid for [[RedshirtArmy even being there]] or destroying the audience's SuspensionOfDisbelief when FiveRoundsRapid ''actually works.'' Not much can be done about this.

It would seem that audiences usually like to see a [[PlayingTennisWithTheBoss more]] [[YourMindMakesItReal creative]] [[CosmicKeystone method]] for destroying the monster than MoreDakka.

There are a few methods for overcoming this, including DepletedPhlebotinumShells and (inexplicably) attaching the very same weapons to another giant robot or monster. On the other hand, simply laying out poisoned bait for these critters and letting their appetites do them in will never, ever, ''ever'' occur to anyone[[note]]Except in Film/GameraVsGyaos[[/note]].

Contrast the SquareCubeLaw, which suggests larger things should actually be ''weaker''. However, assuming that the Square Cube Law is still in effect, and they still don't collapse and die, then this trope is justified. For example, a human scaled up to 12 Feet tall built like a brick house would have to be strong enough to fight Spiderman in order to work.



[[folder: Anime and Manga ]]

* ''Anime/MazingerZ'' and its sequels (''Anime/GreatMazinger'' and ''Anime/UFORoboGrendizer'') played this trope straight. Combat jets, tanks, missiles... could not even scratch the armor of a {{Robeast}}, and it could only be defeated by a similarly giant weapon. It is subverted with the {{FemBot}}s, though, since Aphrodite A, Diana A and Venus A could be easily defeated, and Aphrodite A could be briefly deterred by an army of {{Mooks}} using conventional weapons.
* Of course, this is a staple of the SuperRobotGenre, since it justifies the existence of the HumongousMecha. Since a {{Robeast}} can not be defeated through conventional weaponry, it must be fought with another giant enemy. ''[[Anime/{{Gigantor}} Tetsujin28-Go]]'', the first HumongousMecha played this trope completely straight. It was intended to be Japan's ultimate weapon during World War II. Since that war was over before the robot was finished, Tetsujin is used to fight mostly criminals and terrorists. Other examples are: ''Manga/GetterRobo'' (that battled giant cybernetic DINOSAURS), ''Anime/{{Raideen}}'', the ''Anime/RobotRomanceTrilogy'' -''Anime/CombattlerV'', ''Anime/VoltesV'' (it was supported by the army, but conventional weapons were never strong enough to battle Boazanian's Slave Beasts), ''Anime/{{Daimos}}''-, ''Anime/{{Zambot3}}'', ''Anime/{{Daitarn3}}''...
* In ''Anime/TengenToppaGurrenLagann'', the HumongousMecha are shown to be vulnerable to concentrated small-arms fire (something that [[BadassNormal Yoko]] uses to her advantage on a number of occasions). This hasn't stopped some viewers from asking, "Why are they shooting at the robots when they know it won't do any good?" later on.
* ''Anime/NeonGenesisEvangelion'' takes this one seriously. On the one hand, they try bullets, missiles, and clean nukes on the angels; but [[spoiler:[[AssimilationPlot part of]]]] the reason the Evas exist is that the Angels are protected by a force field (they call it an AT field) that only the Evas can cancel out with their own AT fields. Though there are cases where science fiction-based weapons '''do''' defeat them. For example: [[SinisterGeometry Ramiel]] is destroyed by a high powered energy rifle that requires the use of the ''entire power grid across the entire country of Japan'' to power.
* The trope is averted in ''[[Anime/SuperDimensionFortressMacross Macross]]'' for both the Zentradi and their battle pods. While Zentradi (at least those of Bretai's type) are powerful enough to dismember GiantMecha with their bare hands, human weaponry or Zentradi weapons wielded by humans can take them down in an instant.
* ''Manga/GiantRobo'' takes place in a world where 'Experts' have various superpowers and can duke it out with each other, to the detriment of the landscape. But with a title like ''that'', guess where the ''real'' force is. The show mostly plays it straight - Giant ''does'' equal Invincible, unless you're [[DangerousForbiddenTechnique prepared to die soon afterwards]].
* ''[[Anime/MobileFighterGGundam G Gundam]]'' averts this with [[{{Badass}} Master Asia]]. He can stop mecha-scaled bullets with his bare hands, kill Mobile Suits with his scarf alone, and can punch a building out of the way with his student. Size alone doesn't automatically make anything invincible here. ''Franchise/{{Gundam}}'' in general is all over the place with this trope. The Universal Century series have anti-Mobile Suit infantry tactics being reasonably effective while armies in the Alternate Universes generally don't field infantry against Mobile Suits at all. However one of the series' major conceits is that Mobile Suits can effortlessly take down battleships and Mobile Armors hundreds of times larger than themselves.
* ''Anime/ScienceNinjaTeamGatchaman'' subverts the trope. You only needed the Gatchaman team -a FiveManBand of teenagers with a CoolAirship-to take on a HumongousMecha and destroy it.
* Played with in ''Manga/OnePiece''. While more powerful characters tend to be bigger, giants are easily taken down by the more powerful characters. One subversion is Oars Jr, who, though he could take cannonballs with ease and smash through smaller giants (wrap your brain around that), all it meant for the truly powerful characters was that he presented a bigger target.
* Zigzagged in ''Manga/FullmetalAlchemist''. Envy's [[OneWingedAngel gigantic true form]] is the biggest creature in the series, and focuses more on brute strength than speed. This makes him more than a match for Ed, Ling, and on other characters who are completely unprepared for his transformation. Later when he uses this against [[PlayingWithFire Roy Mustang]], Roy simply flash-fries him over and over, pointing out that all Envy did was give him a bigger target. It also didn't help that they were fighting in an enclosed space that took away any maneuverability Envy might've had elsewhere.
* Subverted in ''Manga/AttackOnTitan''. Titans are actually [[MadeOfPlasticine very fragile]], and not only do conventional weapons damage them without issue.....they're also prone to injuring themselves by accident. The problem is that they FeelNoPain (unless you stab them in the eyes) and have an incredibly powerful HealingFactor, with only [[AttackItsWeakPoint one possible way]] to put them down for good. It makes killing one a very difficult and dangerous proposition.


[[folder: Comic Books ]]

* [[ComicBook/XMen Sentinels]] aren't invincible (yet), but they are built exceptionally tough because their intended targets can [[ComicBook/{{Cyclops}} shatter you with a glance]], [[ComicBook/{{Wolverine}} cut anything]], [[ComicBook/{{Storm}} throw lightning]], [[SelfDemonstrating/{{Magneto}} bend steel with a thought]] or just [[ComicBook/{{Phoenix}} treat matter like tinker-toys]]. As a consequence, we don't often (if ever) see conventional arms used against them.


[[folder: Film ]]

* This could be the reason dinosaurs in the first two ''Franchise/JurassicPark'' movies appear to be bullet-proof. (Though granted, we puny humans rarely get a chance to even try shooting.) They don't seem to be ''completely'' invincible. After all, the hunters in [[Film/TheLostWorldJurassicPark the second film]] are able to catch them in large numbers, and the movie acts as though the head hunter's elephant gun would have worked had the [[DesignatedHero environmental terrorist]] not stolen his ammo. Also, there's the instant death coral poison gun that got [[TooDumbToLive tangled in some cargo netting.]]
* ''Film/{{Transformers}}''
** One of the (many) common complaints against Creator/MichaelBay's [[Film/TransformersRevengeOfTheFallen second film]] is the presence of human soldiers with rifles during the battle. It seems that they're only there because Bay wants to see their bodies pinwheel through the air from explosions. Never mind that we see [[BigBad Megatron]] himself driven back by concentrated fire from the fleshlings.
** By [[Film/TransformersDarkOfTheMoon the third film]], they have learned to take down Cybertronians with ''assault rifles''. Granted, those rifles are firing armor-piercing rounds, but they are shown to be training in tactics specifically designed against large robotic opponents, such as dropping from above and [[EyeScream going for the eyes]]. They still drop like flies, especially when the Decepticons bring out the disintegrator guns, but are able to take down a number of enemy 'bots including [[spoiler:Shockwave]].
*** All of this is justified though. The first movie revealed that humans discovered just what type of man-made weapon capable of injuring a Cybertronian, and actively made that the standard issue ammo for all soldiers in the following films.
* In ''Film/{{Cloverfield}}'', WordOfGod tells us that the traditionally unstoppable monster [[spoiler: was killed by the "Hammerdown Protocol"]], but many fans and the credit sequence seem to disagree.
* Every ''Franchise/{{Godzilla}}'' movie ever. (In the [[Film/{{Gojira}} original]], the "Oxygen Destroyer" kills Godzilla. Still, it's not a conventional weapon, but a 'superscience' type. The [=SuperX=] in much later films has some effect.)
** ''Film/GodzillaVsDestoroyah'' subverts this. Turns out that too much radiation ''can'' kill Godzilla. The downside is that it'll cause him to go into a meltdown and destroy the world. Granted, nuking Godzilla is a bad idea in the first place, since it'll make him larger and more powerful before it has any fatal effects on him.
** Subverted in ''[[Film/GodzillaMothraKingGhidorahGiantMonstersAllOutAttack GMK]]''. Godzilla is defeated after [[spoiler:swallowing a submarine that uses high-powered torpedoes to drill a hole through his chest allowing said submarine to escape, and causing Godzilla to explode by his thermonuclear breath tearing him apart from the inside out via said hole.]] It doesn't kill him, per se, but at least he's been [[spoiler:reduced to a disembodied heart.]]
** In ''Film/GodzillaFinalWars'', fans had every reason to expect invincible kaiju. Ryuhei Kitamura attempted to overcome this trope with superhuman mutants and flying battlecruisers with lasers.
** Part of the reason for the hate for the first American ''Film/{{Godzilla 1998}}'' movie is that this is averted. While Zilla is pretty much immune to small arms fire, big guns and bombs are able to hurt him, and late in the movie he is injured and eventually killed by conventional weaponry.
** Brought back full-force in ''Film/{{Godzilla 2014}}''. The [=MUTOs=] and Godzilla [[ImmuneToBullets shrug off all bullets,]] tank rounds, and sea-to-ground missiles, though rifles successfully distract the [=MUTOs=] more than once. It is confirmed in the movie that Godzilla can survive point-blank nuclear explosions in the kiloton range, though they have no idea what megaton-level explosions will do. However, the nuclear initiation that the movie shows targeting Godzilla is known to us as the Castle Bravo test, which is famous not only for being one of the first multimegaton tests, but for unfortunately exceeding expectations- the expected 4-8 megaton explosion was roughly 15 megatons. No nuke in the current arsenal is capable of that [[note]][[ArtisticLicenseHistory This particular variation appears to be based on only fixating on what can be done with today's "cool DARPA technology" and not considering other factors; while the know-how exists, the political will doesn't]][[/note]].
* Averted with ''Film/{{Rodan}}''. Both monsters die in a volcano while the JSDF bombs them with an air strike.
* Subverted in the 90's ''Franchise/{{Gamera}}'' trilogy. Gamera is easily shot down by missiles. They don't kill him, but they certainly do their fair-share of damage to the giant turtle.
* Averted in ''Film/KingKong''. Kong is gradually shot down by biplanes (Helicopter gunships in the updated remake), and slowly dies from shot after shot.
* Downplayed in ''Film/PacificRim'': the {{Kaiju}} aren't ''entirely'' immune to conventional tanks and bombers, but are so resistant to them it takes days of constant attacks just to kill one, all while the things tear the hell out of cities. The collective world community agreed to [[NuclearWeaponsTaboo stop using nuclear weapons on the Kaiju]], because even though they work, doing it over and over again was far more destructive to the planet an humanity in the short run. The point of [[HumongousMecha Jaegers]] isn't just to kill the things, but to kill them ''quickly''; preferably before they even reach the coast.The Kaiju eventually built a nuke-proof variant anyway.


[[folder: Literature ]]

* Averted in ''Literature/TheScar'', where the gargantuan avanc slowly succumbs to infection after it gets injured by the grindylow. We don't actually see what weapons they'd used to damage it, but the lakeful of pus it emits while ailing is a definite sign that it's the infection, not the wounds themselves, that proves fatal.
* Averted in ''Shadow's Fall'', where the "unpowered" retired super hero Lester Gold takes on a T-Rex by tricking it into swallowing a grenade, leading to "your head asplode". Played straight with the Great Wurm, Cromm Cruach.
* This is certainly the characters' initial reaction to the skyscraper-sized vordbulks in ''First Lord's Fury'', the final book of Jim Butcher's ''Literature/CodexAlera'', but then a few bright sparks work out [[AttackItsWeakPoint their weak points]]...
* Averted in Taylor Anderson's ''Literature/{{Destroyermen}}'' series, where the alternate Earth features many extant dinosaurs and other giant creatures (such as Mountain Fish, which are enormous whale-like creatures that eat ships for breakfast). Enough bullets, especially firing at eyes or opened mouths will bring down any creature. Hell, several times, attempts to ''scare off'' a Mountain Fish resulted in their accidental death. Turns out it can't handle a depth charge very well. In fact, one of the main characters, a BoisterousBruiser named Dennis Silva, turns a Japanese anti-aircraft gun into a {{BFG}} musket he calls the Doom Whomper, designed specifically to hunt the allosaur-like superlizards but doubling as a sniper rifle in a pinch.
* Zigzagged in the ''Literature/ProjectNemesis'' series. The natural black armor on the kaiju protects them from anything the military throws at them, including a M.O.A.B.. However, their armor is not completely impenetrable and if removed, their soft, pale skin underneath is susceptible to conventional military fire.


[[folder: Live Action TV ]]

* ''Series/{{Ultraman}}'' lives on this. The Science Patrol always attacks the MonsterOfTheWeek with EnergyWeapon handguns, airplanes, etc., but typically only Ultraman -- once he's grown to the same scale as the rampaging monster -- can actually defeat the monster. Averted occasionally -- for example, it's the Science Patrol that actually destroys Zetton (the monster who "kills" Ultraman). It takes circumstances and (often) special one-of-a-kind weaponry, but the human teams ''are'' capable of protecting Earth on their own. It's even better when the team and the Ultra cooperate.
* A lot of Japanese {{Toku}}satsu shows play this fairly straight, pretty much following the examples of ''Franchise/{{Godzilla}}'' and ''Series/{{Ultraman}}''. In fact, anytime a human-scale character offs a building-sized one, it's likely to be a [[SugarWiki/MomentOfAwesome CMOA]] of some sort.
* In ''Franchise/PowerRangers,'' if you don't have a HumongousMecha, you should basically run. It's ''exceedingly'' rare that the most godlike weapons used at human scale can scratch the monster after MakeMyMonsterGrow ensues. And yes, it ''is'' freaking awesome and remembered forever when a Ranger manages to avert this. (As you can imagine, of the three times it happens, once it was [[LawOfChromaticSuperiority a Red Ranger]], once it was a SixthRanger, and once it was [[MemeticBadass Tommy]].)
* Played straight in ''Series/TerraNova''. Even dinosaurs that are only slightly larger than people shrug off small arms like they're nothing. Even the mounted wave cannons on the walls of the compound only repel a ten foot tall dinosaur.


[[folder: Newspaper Comics ]]

* Parodied by one of the final unpublished strips of ''ComicStrip/TheFarSide'', available in ''Last Chapter And Worse''. A man is interviewed after taking down a Godzilla-like monster with his shotgun. "Well, I seen all the commotion, with that there monster destroyin' half the city and whatnot, and I says to myself 'Hell! Why don't someone just shoot the varmint?'"
** Also averted in one depicting a massive, slain mastodon, [[AttackItsWeakPoint with a miniscule arrow in its buttock]].
-->'''Caveman:''' Maybe we should write that spot down.
** As a GeniusBonus, this is one of the theories about what spurred early man to invent writing.


[[folder: Roleplay ]]

* ''Roleplay/DestroyTheGodmodder'' follows this sometimes, and other times throws this out the window. It all depends on if said giant beastie is the godmodder's or something one of the players summoned.


[[folder: Tabletop Games ]]

* Averted in ''TabletopGame/{{GURPS}}''. Whenever a single giant monster appears, the players tend to take it out with a single shot to the eye. Creatures that big tend to have eyes that are easy to hit, and damage multiplier tends to make even a T-Rex go down in one or two hits.
* In ''TabletopGame/DungeonsAndDragons'', bigger monsters tend to be tougher, but not necessarily ''because'' they're bigger. Bigger monsters are also bigger targets.[[note]]-1 AC for each size category above Medium (e.g. most humanoids)[[/note]]
** The Titanic template[[note]]templates modify the 'base creature' they are applied to -- Titanic is designed to make a medium-sized or smaller animal into a gargantuan-sized animal[[/note]] is a downplayed version of this trope -- it is entirely possible to kill Titanic creatures using ordinary weapons, but they have a lot more hit points than the base animal, and a lot of natural armor (meaning that, due to what AC and Touch AC represents, they are a lot easier to hit, but roughly as easy to somewhat harder to hit well enough to actually do any damage).
* Played mostly straight in ''TabletopGame/{{Warhammer 40000}}''. Big monstrous creatures like [[BeastOfBattle Squiggoths]] or the larger [[HordeOfAlienLocusts Tyranid]] bio-forms (to say nothing of [[HumongousMecha Titans]]) have such a high Toughness or Armor Value that most standard infantry weapons are incapable of dealing damage to them. That said, even basic infantry squads can purchase a specialist weapon like a missile launcher or meltagun, so such big, nasty, expensive units ignore infantry at their peril. Furthermore, certain units fire special poisoned rounds that are effective against any creature regardless of Toughness, while sniper rifles have a similar rule representing how their wielders are able to target weak points.
* Averted in ''TabletopGame/BattleTech''. [[HumongousMecha BattleMechs]] may be the more-or-less official "kings of the battlefield" and heavier designs are tougher than lighter ones, but they're still only glorified ''tanks'' on legs and remain vulnerable to lucky hits and cumulative damage from even 31st century infantry weapons assuming the infantry can live long enough to get into range and exchange fire with them for a while. (Urban combat in particular can become a legitimate nightmare for them.)


[[folder: Video Games ]]

* ''VideoGame/MechAssault'' and ''VideoGame/TheIncredibleHulkUltimateDestruction'' both have harmless infantry enemies. The former is excused in that they're members a a fanatical cult who aren't afraid to die. The latter are member of the US army, but they'll try to avoid the Hulk...for the most part. If he can get close enough, they'll try rifle-butting him, which works about as well as you'd expect.
** ''VideoGame/MechAssault'' and the ''VideoGame/{{Mechwarrior}}'' series it spun off from actually zigzag quite a bit with this trope. FiveRoundsRapid can't do much to even a scout Mech barring ''extremely'' extended attrition but a single properly placed satchel charge can bring even a hulking Assault-class machine down and clan [[PoweredArmor Elementals]] (or IS Battle Armor) can take down ''several'' Mechs alone if the wearer is skillful.
** The effective variant tends to rely more on [[AttackItsWeakPoint damaging a vulnerable spot]] via HumongousMecha {{Kneecapping}}. Most of the games where non PoweredArmor-wearing troops fire infantry-scale weapons at 'Mechs don't include this tactic, and examples such as ''Mechwarrior 3'' messily demonstrate why an average human shouldn't be anywhere ''remotely'' near a 'Mech.
* The ''VideoGame/{{Earth Defense Force|2017}}'' series gleefully averts and inverts this. You play as a wimpy looking guy in a baggy jumpsuit who is tasked with killing swarms of giant bugs, towering mechs, kaiju, flying saucers, and walking fortresses. On foot. With conventional weaponry like assault rifles and shotguns. And it works!
* The ''VideoGame/MonsterHunter'' series averts this trope in its later monster hunts.
* In the ''VideoGame/DragonBallZBudokaiTenkaichi'' series, giant characters will not flinch at most smaller character's punches and almost all rush moves will ricochet off them before they can do anything. This means characters like Hercule and Videl are almost completely helpless against them.
* Generally averted in ''VideoGame/WorldOfWarcraft''. Giants are met pretty often and while they usually can easily stomp a lone adventurer of an appropriate level, the tactics for taking them down is to bring friends and kick it's ass as a team (of varying sizes). Your human- (or dwarf- or even a gnome- or a goblin-) sized 'tank' will weather the giant's stomping as well as he does normal-scale enemies'. Only few quests are centred on driving or riding another giant and wrestling the monster giants on their own scale - and in these cases the trope often plays in your favour in regards to normal scaled monsters.
* Subverted in ''VideoGame/AsurasWrath''. The first boss, Wyzen, grows to the size of a planet, then tries to [[FingerPokeOfDoom poke]] the man-sized Asura to death. Asura blows him up, and he is posthumously mocked by his allies for thinking it would work.
* Averted by giant transformers Omega Supreme and Trypticon in ''VideoGame/TransformersWarForCybertron'', who despite massive their size advantages can be defeated by conventional transformers. Played straight by Metroplex in [[VideoGame/TransformersFallOfCybertron sequel]] who is only once slowed by enemy assault.
* Averted in the ''VideoGame/{{Rampage}}'' series where the player controlled monsters are vulnerable to, not only missiles, but small arms fire. Of course it can take a lot to kill them depending on the player.
* In the ''VideoGame/ClashOfClans'' commercials, the Giants are portrayed as being colossal guys who laugh as cannonballs, arrows, and mortar shells bounce off of their skin. [[GameplayAndStorySegregation In the game]], they are only about three times bigger than a Barbarian and are just [[MightyGlacier very tough]], not invincible.
* Technically averted, but played straight in any practical sense in the "Hoth" level of ''Shadows of the Empire''. While you certainly ''can'' take a full AT-AT down with your blasters, it will take a really, really long time. Using your harpoon and tow cable to go for the legs is not only much faster and easier, but infinitely cooler.


[[folder: Web Original ]]

* EVERY. MACROPHILE. STORY. EVER. Every one there has ever been or ever will be uses this Trope extensively, and even taking it to ridiculous extremes. Some stories, artwork, and etc do try and be more intelligent about it. Though as often as they run afoul of the SquareCubeLaw, most handwaves for that issue tend to get applied to this trope as well.
* Averted in ''Literature/TheSalvationWar'', where despite both the Demons and Angels being much larger than humans, they go down easily due to modern weaponry.
* ''{{Literature/Worm}}'': the only way to fight an [[{{Kaiju}} Endbringer]] is to throw hundreds of [[SuperHero capes]] at it at the same time. No gun, explosive, nuclear bomb or other human weaponry can harm it, save for AppliedPhlebotinum.


[[folder: Western Animation ]]

* An episode of ''WesternAnimation/DextersLaboratory'' plays with this one: they accidentally awaken a giant Kaiju monster (it specifically happens in Japan, so it's a clear parody). The monster stomps all over a variety of superheroes and small superweapons and isn't defeated until they assemble a giant Anime/{{Voltron}}-esque robot. Though that was supposed to be an Aesop about family togetherness more than giant robots.
* ''WesternAnimation/ReBoot'', episode "Nullzilla" - which played off kaiju and mecha movies. The monster had to be stopped by creating a CombiningMecha.
* In ''WesternAnimation/TheSimpsons'' "Treehouse of Horror VI", giant advertising mascots go on a rampage. Predictably, conventional weapons are useless, but it turns out that [[YourMindMakesItReal our attention makes them real]] and they'll [[GodsNeedPrayerBadly keel over]] if we just don't look.
* If it comes to that, even ''baby'' dinosaurs in ''WesternAnimation/TheLandBeforeTime'' are harder than rocks of the same size. Although maybe it's more that those are some really sissy rocks.
* In ''WesternAnimation/MonstersVsAliens'', the army throws its entire arsenal at the giant alien robot without leaving so much as a scratch. And even after that, the President shoots a few rounds at it, just to show that he's a brave president. It is then that they decide to [[SummonBiggerFish sic the monsters at it]], but even ''they'' have a hard time defeating it. Considering that even the largest of the "monsters", [[AttackOfThe50FootWhatever Ginormica]]/Susan, is still tiny compared to the robot, this is justified.
* ''WesternAnimation/MyLifeAsATeenageRobot'' has Armagedroid, an older HumongousMecha designed by Dr. Wakeman, which fits this trope to a T. There are a couple of other [[MonsterOfTheWeek giant-sized threats]] throughout the show, but Jenny is able to beat them with some sort of force.
* Despite the aversion in the American ''Godzilla'' film, ''WesternAnimation/GodzillaTheSeries'' plays this straight. Godzilla in this series, is now capable of taking multiple hits from human ''AND'' alien weaponry. Not only him, but the [[MonsterOfTheWeek other monsters that appeared in the series]]. The only time they would die is by Godzilla or the Leviathan alien's weapons. And fighting each other.


[[folder: Real Life ]]

* Perhaps not as ridiculous a trope as it seems; a 50 meter tall, 20,000+ ton monster would most certainly ''need'' to be made of a very strong and durable substance, simply to ''[[SquareCubeLaw keep itself from falling apart at the seams]].'' Any monster that huge that was so flimsy as to be vulnerable to conventional weapons would be squashed by its own mass before we'd ever need to fire a shot. If on the odd chance you ever do [[TemptingFate meet a kaiju IRL]] and it doesn't collapse into jelly the moment it steps out of the ocean, you can [[GenreSavvy safely assume this trope is in effect]].
* Considering a simple hunting rifle can bring down an elephant, this is definitely not TruthInTelevision, even in the rare cases there are big things to shoot at.
** With a much more relative definition of "giant", this applies to all macroscopic life. Nearly anything can be taken down by an infection by much smaller organisms (such as bacteria or viruses).
** They are resistant to many small arms fire, that is what [[{{BFG}} elephant guns]] are for.
*** Elephant guns aren't strictly necessary for elephant hunting. In the olden days of unregulated slaughter for ivory many an elephant was killed with the lowly 7x57mm hunting cartridge, today now mostly used (at least in the United States) to bring down the relatively tiny whitetail deer. The main advantage of said "elephant guns" was that they could bring down very large game more quickly and more reliably. You could kill an elephant with a 9mm pistol if you had to, but it'd take a while (not as in shooting it until it dies video game style, but rather in waiting for it to bleed out, or with less severe injuries, wait for an infection to develop, since a small cartridge would have a hard time piercing the skull or penetrating to an internal organ). A more powerful firearm has the advantage of being able to bring forth a quicker death from farther away (which helps considering that said elephant may be trying to kill you), but once it dies, dead is dead one way or another.
** Whales can be killed with a simple harpoon, but its not as easy as it seems as they need to nail it at the right spot to make it effective. Then came grenade harpoons.
* RealLife massive vehicles of both civilian and military types are largely immune to or not significantly compromised by most small-arms fire, which is the reason that specialized anti-vehicle and anti-materiel weapons (which often have firepower on the same scale as the vehicles themselves) exist. Giant aircraft are slightly more susceptible due to the mechanical balancing act that keeps them aloft but a platoon of infantry would still need a ''lot'' of lucky assault rifle shots to down a heavy bomber if it somehow came within range.