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[[quoteright:341:[[Webcomic/{{Erfworld}} http://static.tvtropes.org/pmwiki/pub/images/cavemouth_7797.png]]]]

->'''Kidnapper:''' We'll be fine. Trolls run from fire.
->'''Rincewind:''' Yes, but... this one can't, you see.
->'''Kidnapper:''' And why's that?
->'''Rincewind:''' Well, because... you've lit it on his ''tongue.''
-->-- ''Discworld/TheLightFantastic''

There's a good reason the entrance to any underground cavern is called a "mouth".

Consider that the mouth is a breeding ground for bacteria[[note]](both good and bad)[[/note]]; it's dark, and damp, too, and has a lot of sharp objects lining its roof and floor.

Now consider a typical cave: Dark, possibly damp, a breeding ground for all sorts of unsavory creatures, with stalagmites on the floor and sharp (and occasionally [[StalactiteSpite falling]]) stalactites lining the ceiling...

So is it any wonder that sometimes authors can't resist making a VisualPun out of the "mouth" to a cave?

Sometimes this goes beyond the visual metaphor and actually becomes a plot-relevant -- perhaps [[ThatsNoMoon That's No Cave]].



[[folder:Card Games]]
* The card Howling Mine from ''TabletopGame/MagicTheGathering'' looks like this most of the time, DependingOnTheArtist.

[[folder:Comic Books]]
* One comic of ''Franchise/ConanTheBarbarian'' has a rather literal example of this. In his efforts to steal two strangely eye-like (yet angled) gems from a greedy merchant, Conan and the merchant both go chasing after the gems when they start flying through the air, leading them through a strangely mouth-like cave (with irregular sets of "teeth" set the whole way through) to a large central chamber that is covered with deep piles of gemstones. The merchant immediately dives into the mixed array of rubies, diamonds, sapphires, emeralds and other gems, noting that it's extremely strange to see so many different types of gem in the same place, but too blinded by greed to care. Conan is more cautious, and thusly he survives when it turns out they're in the stomach/throat of some kind of mountainous earth elemental. The merchant is devoured.
* ''ComicBook/TalesOfTelguuth'': A brother and sister who are about to be offered as the final sacrifices required to resurrect an evil god run away from the priests and take shelter in a cave in the desert. When the brother climbs out it turns out that the cave was really the mouth of the god, who eats the sister so it can rise from its slumber and lay waste to the world.

[[folder:Comic Strips]]
* ComicStrip/ThePhantom lives in [[ExactlyWhatItSaysOnTheTin the Skull Cave]], which is an obvious example of this trope.
* A ''ComicStrip/{{Dilbert}}'' comic had a cave with an entrance [[http://dilbert.com/strips/comic/2004-03-17/ that resembled a somewhat different orifice]]. The previous comic did say that Asok had to travel to "the bowels of the bureaucracy"...

[[folder:Films -- Animation]]
* In ''Disney/{{Aladdin}}'', the Cave of Wonders' opening is a big tiger's mouth with sharp teeth. It also talks. ("Who disturbs my slumber?")
** ''Disney/AladdinAndTheKingOfThieves'' has a huge turtle whose mouth was like a cave.
* In Disney's ''Disney/TheLittleMermaid'', the front door of Ursula's lair is the mouth of a sea-dragon skeleton.
* Monstro's mouth in ''Disney/{{Pinocchio}}''.
* The Cave of the Beast in ''The Twelve Tasks of ComicBook/{{Asterix}}''. Bonus points for closing after they enter.
* In ''WesternAnimation/TheBraveLittleToaster'', the [[FiveManBand gang of appliances]] is seeking shelter and Lampy discovers a hollow tree. He hops in, calls to his friends, then turns on his light. From the outside, the illumination creates a scary face like a jack-o'-lantern, and everyone else screams and vanishes into the bushes. Lampy can't see it because he's inside the tree itself, once he figures it out, hilarity ensues.
-->'''Lampy''': [[ScreamsLikeALittleGirl OOH-WAAH-OOH-WAAH-OOH-WAAH-OOH-WAAH!!!!!]]
* In ''WesternAnimation/ThePagemaster'', our heroes find a cave, which is full of stalagmites and stalactites. When Adventure accidentally breaks one, it's revealed that the "cave" is actually the mouth of a dragon.
* [[Creator/TimCurry Drake's]] island from ''WesternAnimation/ThePebbleAndThePenguin'', which for some reason looks like it should've suited Frankenberry more than an evil penguin.

[[folder:Films -- Live-Action]]
* ''Film/TheEmpireStrikesBack'' have the crew of the Millennium Falcon confuse a Space Slug's mouth with an asteroid cave.
* In ''Film/TheGoonies'', there is a skull-shaped cave entrance.

* In the eleventh ''Literature/GiveYourselfGoosebumps'' book, Deep in the Jungle of Doom, one path has you entering a cave that is strangely damp, with soft pink walls. It turns out you're in the mouth of a giant rock monster, and your friend let it eat you in exchange for her own life. Naturally, this is a BadEnding, and ends with you being SwallowedWhole and waiting for death as you plunge towards the stomach...

* In ''Literature/TheCatastropheOfTheEmeraldQueen''. The entrance to The Shores.
* In ''Discworld/TheLightFantastic'' Twoflower's kidnappers inadvertently settle in the mouth of an enormous troll, mistaking it for a cave. They probably would have been fine if they hadn't lit a fire inside it, ironically to ward off trolls.
* In ''Literature/TheSeventhTower'' cavernmouths look like regular caves... except for gleaming red dots. These are tonsils, and if you stray too close to the "entrance"... the jaws come out.
* The gate to the Colony in the ''Literature/{{Tunnels}}'' books is called the Skull Gate, because it rests below an enormous stone skull.
* In the ''Literature/TheSprigganMirror'', the castle- presumably Derathon's- was said to have the only entrance carved like a gaping mouth.
* In the ''Literature/WarriorCats'' series, the cats call a certain cave "Mothermouth" because it resembles a mouth.

[[folder:Live-Action TV]]
* In ''Series/TheTenthKingdom'', the cave entrance is not just shaped like a dragon's head, it's an actual dragon's head. A dead, fossilized dragon (hence the name "Dragon Mountain"). This introduces a bit of Squick when the cast must take mining sleds down along the spine and ribs toward the actual mine and get tossed out the other end.
* In the ''Series/StarTrekTheOriginalSeries'' episode "The Apple", you've got the mouth of Vaal, a cave mouth shaped like a dragon's head, complete with glowing eyes.
* The Cave of the Golden Rose from ''Series/{{Fantaghiro}}'' is actually a monster's mouth, and the rose is its uvula. The cave even gave its name to most translations.
* ''Series/TheGoodies'' go caving. They find a remarkable Cave Mouth. They note the curving rows of stalagmites and stalactites and treat the odd red thing [[note]]uvula[[/note]] like a punching bag. The giant dinosaur, naturally, closes its mouth on them.
* ''Series/DoctorWho''. In ''The Face of Evil'' a giant face of the Doctor has been carved into the cliff by the mad computer. The Doctor indignantly rejects the idea that they enter the cave by climbing up 'his' nostrils. "It's up over the tongue and down the throat."
** Similarly the [[Creator/PaulMcGann Eighth]] Doctor encounters a creature who was a mountain, and its many cave entrances [[Recap/BigFinishDoctorWho055TheTwilightKingdom part of him]].

[[folder:Tabletop Games]]
* ''TabletopGame/CallOfCthulhu'' supplement ''Fragments of Fear'', adventure "Valley of the Four Shrines". The entrance to the cave that leads to the valley has been carved in the likeness of Cthulhu's head.

[[folder:Theme Parks]]
* The Storybook Land boat ride at Disneyland begins by entering Monstro the whale from ''Disney/{{Pinocchio}}''.
* The queue line for ''Ride/SkullIslandReignOfKong'' at [[Ride/UniversalStudios Universal's Islands of Adventure]] goes through several cave caverns, which have mouth-like archways scattered throughout.
* Great America's roller coaster The Demon has featured a high-speed plummet into a CaveMouth since its theming in 1980.

* ''Toys/{{Bionicle}}'': the entrance to [[http://biosector01.com/wiki/index.php/File:Roxtus.PNG Roxtus]], which isn't surprising as it's the head of a [[HumongousMecha Prototype Robot.]]

[[folder:Video Games]]
* ''Franchise/SuperMarioBros''
** In ''VideoGame/SuperMarioBros2'', every level's exit is a Mask Gate, shaped like a huge bird head.
** Also, the map icon for "Bowser's Galaxy Generator", the final level of ''VideoGame/SuperMarioGalaxy2'', which is actually shaped like [[BigBad Bowser's]] head.
** As with the map icons for the first two Bowser levels in the original ''VideoGame/SuperMarioGalaxy''. And the fish planet in Bigmouth Galaxy.
* In ''VideoGame/QuestForGloryIV'', the cave you start in the beginning. [[spoiler:It turns out that it's an EldritchAbomination.]]
* The entrance to the Sea of Black Tears in ''VideoGame/BrutalLegend'' is shaped like a giant skull.
* Grunty's lair from ''VideoGame/BanjoKazooie''.
* The entrance to a cave in ''VideoGame/FinalFantasyAdventure'' not only looks like a mouth, it has a sense of taste as well, and will spit you back out if your armor isn't tasty enough (it likes silver).
* One level of ''VideoGame/GoldenAxe 2'' takes place in "the cavern called Dragon's Throat". Guess what the entrance looks like?
* In ''VideoGame/DarkFall: Lost Souls'', Amy's creepy drawing of Dowerton Station depicts the entrance to the train tunnels like this.
* Almost all the dungeon entrances in ''VideoGame/TheLegendOfZeldaI'' consist of these. ''VideoGame/TheLegendOfZeldaSkywardSword'' also features a couple as a CallBack to the first game.
* El Diablo's cave in ''VideoGame/{{Desperados}}'', as a skull.
* A giant monkey head serves as the entrance to the caverns of meat in ''VideoGame/TheSecretOfMonkeyIsland''. The head itself is attached to a giant skeleton buried underground...
* The Tyrano Lair in ''VideoGame/ChronoTrigger'' features doors styled after theropod maws which open and close depending on switch configuration.
* Two entrances to the Annihilator Factory in ''VideoGame/HeroCore'' have a mouth design.
* The cave entrance to the [[FireAndBrimstoneHell Oubliette of Suffering]] in ''VideoGame/{{Shantae}} and the Pirate's Curse'' is one with its "teeth" initially blocking the way. [[GeniusLoci It will only open its mouth]] to stinky ne'er-do-wells.

[[folder:Web Animation]]
* The cave in which Lewis was murdered in ''WebAnimation/MysterySkullsAnimated'' had an eerie mouth like opening with four holes above it that looked like nostrils and glowing eyes due to the green entity in the cave.

[[folder:Web Comics]]
* Pictured above, in ''Webcomic/{{Erfworld}}'', the entrance to the caves leading to Gobwin Knob has a sinister resemblance to a mouth.
* Invoked in ''Webcomic/LookingForGroup''; the party comes across a secret door that expands and contracts; Richard mistakes it for "A mountain that eats people".

[[folder:Web Original]]
* ''Felarya'' is another fictional setting where it is rarely wise to explore such cavern mouths, since the ambush predators tend to be of sufficient size.

[[folder:Western Animation]]
* In ''WesternAnimation/{{SpongeBob SquarePants}}'', Sandy goes into what she thinks is a big pink cave and punches out what she thinks is the [[SandWorm Alaskan Bull Worm]]. She had actually walked straight into its mouth and beat up its tongue.
* In ''WesternAnimation/MightyMax'', the cave entrance is not just a dragon's head, it's an actual dragon's head.
* Done in "In Search of the Dungeon Master", an episode of ''WesternAnimation/DungeonsAndDragons''.
* In a ''WesternAnimation/LooneyTunes'' short called "The Mouse That Jack Built", a cat disguises itself as "The Kit-Kat Club," a night club with a cat-shaped entrance. Its tongue provides the red carpet.
* The entrance to Hell seen in ''Disney/PlutosJudgementDay'' is a large, cat-shaped cave (which coincidentally resembled the entrance to the Cave of Wonders seen in ''Disney/{{Aladdin}}'' many decades later) in the middle of a volcanic area.
* An episode of ''WesternAnimation/DragonTales'' had a giant cave turn out to be the mouth of a giant rhinoceros (who also had a RibcageStomach).
* Chase Young's lair from ''WesternAnimation/XiaolinShowdown''.
* In "Not Very Nice" of ''WesternAnimation/TheTrapDoor'', Berk drops one of the Thing Upstairs' eyeballs down the Trap Door and goes down looking for it. He finds it in a cave that turns out to the mouth of one very large creature;
-->'''Berk:''' Yech! There's that horrible smell again! Hang on, there's sommit funny about this place. [[ExplainExplainOhCrap The walls are slimy, and that green thing looks like a tongue, and them things over there look like teeth... Ohhh, globbits!]] I'm inside the mouth of some horrible thing!

[[folder:Real Life]]
* A chamber in Virginia's Luray Caverns has an entrance like this.
* Some ambush predators can do this to smaller, not-too-clever prey such as bait fish (For example, the alligator snapping turtle for one thing).
* The museum in Copan, Honduras (a major Mayan site) has an artificial mask-style carving of a head for an entrance.
* Be honest, this is how you ate Teddy Grahams or Goldfish as a kid.
* The old Sri Lankan royal fortress was called the Lion's Mouth, because it could only be accessed through a gate that was carved to look like the gaping mouth of a lion. Enormous paws were carved below the gate. These paws still stand today, while the mouth is gone.
* The entryway to Gatorland in Florida is meant to look like a giant alligator mouth.
* One defunct restaurant chain called "[[https://en.wikipedia.org/wiki/Coon_Chicken_Inn Coon Chicken Inn]]" (which got a namedrop in ''Film/CSATheConfederateStatesOfAmerica'') designed its entrances to resemble the mouth of a smiling African American porter, represented in stereotypical {{blackface}} style.