Characters traveling through ventilation systems in fan works.
Among Us
- Among You: In like son, like father, in order to avoid being caught eating Blue's body, Orange escapes Medbay through a vent, going into Electrical.
- In A Princess, a Treehugger, and a Space Cadet Walk Into a Library, Tobias and Marco fall out of an air-vent and into the library.
- The absurdly spacious ones in Arkham are viciously lampshaded in Bruce Has a Problem; evidently they were originally dog runs put in by a director who thought dogs would have mental healing properties, abandoned when the director died in a dog-petting accident. They were then repurposed as vents by another director, who was looking to cut costs to fund a step pyramid he was building.
- Both played straight and deconstructed in "Of Friends and Foes."
Robin and Kid Flash decide to sneak through air vents to eavesdrop on the JLA meeting for fun, and the size of the vents is explained away as being large enough for adults to come and work up there if a problem arises. However, it's noted that Robin still has to use his agility to get around, that it's pretty dirty, and that the boys have to keep their voices down to avoid being heard. Since one of the members has super-hearing and X-ray vision, one has Hyper-Awareness, and another is a telepath, it doesn't go too well anyway.
- Examples from the Calvinverse:
- Calvin ends up using one of these in Retro Chill.
- Inverted in Calvin & Hobbes: The Series: Andy and Sherman are captured by a possessed air vent.
- Calvin and Hobbes use this to infiltrate a base in Trouble Island.
- The The Midnightverse story Diamonds In The Desert is practically about this.
- Also from the same series, Zipper gets into and out of the National Institute for Mental Health via air vents in Lost And Found, and the Rangers use the air-conditioning vents to get into Mr. Jacob's penthouse in Last Date.
Crossovers
- In the Portal/My Little Pony: Friendship Is Magic crossover Better Living Through Science and Ponies, Chell uses some vents to get back inside the Enrichment Center. Justified in that her small pony body fits better.
- Lampshaded in Child of the Storm, wherein Clint (and later, Bucky) like to crawl around in them to get into HYDRA bases (or in Clint's case, just because he likes crawling around in the Avengers Tower ones). Tony freaked out the first time. Now, being Tony, he still likes to pretend he has no idea of what's going on and send his robots to flush them out.
- In the sequel, Bucky notes that they'd be amazed at how many HYDRA bases he's broken into, a point he's apparently previously made to Harry. Harry, however, prefers making his own doorways. Or using Doctor Strange as a chauffeur. As he loftily puts it, "One makes a statement, the other is economical.”
- On a related note, it's become solid fanon in the Avengers fandom that Clint likes doing this. A lot.
- Code Wings 3.0: Jeremie and the others use the ventilation shaft to their new room to evade the whitecoats and Erasers.
- Equestrylvania: In Book 2, after Rainbow Dash and Shatterstom are captured by Rose Blade, he has the former locked in a bathroom that's been converted into a holding cell/torture chamber; after getting free of her chains, she gets out of the room this way. Somewhat subverted, as it's a cramped fit, and Rainbow Dash is constantly worried that she's going to make noise and alert the Mooks below.
- In Fallout Equestria: Pink Eyes, the main character Puppysmiles is just a little filly, meaning it's easier to crawl around in tight spaces. She uses this to enter a locked-down fortress to search for her mom.
- In Manehattan's Lone Guardian, Illudere is crazy enough to try using one of these to get from place to place. However, it almost ends poorly for her: while the vents are just barely large enough for her to fit, her armor adds enough width that it makes traversing them an exercise in tedium, causing her to take hours just to get from a bedroom to the kitchen even with the aid of magic.
- Used regularly by Terawatt in The Secret Return of Alex Mack to enter buildings held by hostiles, and justified by her combination of powers; her silver puddle form can slip through standard sized vents, and her telekinesis means that weight isn't an issue.
- In the Persona/Super Smash Bros. crossover SSB The Return, Melody uses these to get around the school.
- In the Mega Crossover Super Network Wars episode 27, some members of the Nueva Liga Filipina have to crawl through this in order to stop the poisons from being administered into the food of the VIPs at the 12th ASEAN Summit.
- Part of the caper plans in the Undocumented Features fic Hellbringer and the After-School Special Mission Force #1: "The Bad Bank Caper" — as Lain Iwakura says, "Oh, good... I was -hoping- we'd be hitting all the cliches on this job."
- This is how Carlos leaves the VILE base in the Where's Waldo/Carmen Sandiego crossover Where on Earth, Spies. He's a small dog, so it works.
- Where the Sunlight Ends: Subverted; the air-vent that Peter One sleeps in during the time between the climax of No Way Home and that film's epilogue is cramped and uncomfortable, so Peter doesn't plan to use it for anything other than storage and sleep while he hunts for an apartment.
- This is Eric's favorite method of travel in the Spah Verse, both at Dalton and McKinley.
- In the AU series The Darkness Series, Harry uses this when doing spy work at Riddle Manor in snake form.
- This is the method that Draco uses to get the Death Eaters into Hogwarts in A Very Potter Musical.
- Zig-Zagged in a weirdly justified way in Heroes of the Desk—the air vents at a university facility are not large enough for a full-size human (averted), but a 14" tall Hero character can crawl through them (played straight—supercomputing buildings need a lot of cooling).
- Hitman Miami: In chapter 8, the only way into the target's office, apart from a locked steel door, is a six-inch wide vent in the ceiling, which Agent 47 uses to drop monkey chow into the room in order to lure in a Killer Gorilla, then a grenade to kill the gorilla.
- The Victors Project mentions that The Boy form District 5 did this during the 62nd Hunger Games (where the arena was a mansion). During a return to that same arena after Katniss is kidnapped by remaining Capitol loyalists, Justus uses this to ambush members of the rescue party.
- The New Adventures of Invader Zim: In Season 2 Episode 11, the Resisty and Team Save Earth sneak into the building where the Invaders' tournament is being held through the air vents. A Deconstructed example though, as they barely fit in the cramped space and struggle to squeeze through.
- Jackie Chan Adventures: Olympian Journey: Jade, Jimmy, and Rachel do this to escape a crowd of Eros!Drew's brainwashed love cultists, though Rachel is a bit too big for it and has to go through the rafters instead.
- Queen of All Oni: Drago uses the air vents to break into Section 13. He calls it a cliche, and expresses disappointment that the Section 13 of the present isn't on the same level as the one in his time.
- During the Final Battle, Jade and Hebi use the chaos of her forces' invasion of Section 13 as a distraction to sneak into the air vents and use them to get to the Vault unseen.
- One chapter of I Think Some Serious Physics Just Happened has a nice deconstruction of the trope when Ron, dropped into the real world, sneaks into a library through the airvents and naturally gets dirty while crawling through them. Then he starts to wonder why the vents in the supervillains' lairs were never less than spotless. Who was cleaning them? How? Why?
- It's often a good idea to clean out ventilation systems to increase air-flow efficiency, reduce allergens, and stop a significant layer of dust accumulating on everything in the building every night. Particularly in warehouses with the giant ventilation systems that someone could actually crawl through.
- Or there might simply be enough traffic in the ventilation system of the average villain lair to prevent dust gathering... Let's face it, those bases usually last a month or three, and see twenty-odd people getting around by air vents in that timeframe.
- In To Bebe or not to Bebe, Kim and Ron are captured by a surprisingly competent villain who not only has air vents too small to crawl through, but also took all their equipment and destroyed it rather than leave it out to pick up when they escape.
- Missing Linc: Lana is forced to use the air vents to escape after Lindsey Sweetwater locks her in the dressing room.
- Justified in Mass Effect: Human Revolution: Ventilation passages in Krogan battle barges are huge because they're really meant for defenders to outmaneuver boarders.
- Used for infiltration in Masses to Masses. Subverted when Ian's weight brings it down, resulting in Melanis lecturing him on how this trope doesn't work in real situations.
Mermaid Melody Pichi Pichi Pitch
- Mermaid Melody Pichi Pichi Duo: In chapter 8, the group uses one to sneak into the aquarium and find the missing Hanon. It ends up backfiring on them when they end up falling down a chute and landing heavily.
My Little Pony: Friendship Is Magic
- Earth and Sky: After Chrysalis is arrested and thrown in the dungeon in Los Pegasus, she slips free of her chains by molting to filly-size and then crawls out through a vent. Even then, it only works because, as Luna points out, her carapace hasn't hardened yet, allowing her to squeeze through the tight space.
- In A Brief Moment of Culture, Artie hides from a mind-controlled Mell in the ventilation ducts. Justified because tiny little gerbil; it's made clear a human would have trouble fitting an arm in the ducts. And then subverted when Mell begins methodically smashing the ducts from one side to the other, which admittedly isn't something you can do with human-sized ones.
- HERZ: In chapter 4 Kurumi used a ventilation shaft to reach Terminal Dogma after being told it was off-limits.The grill made a tremendous clanging sound as it crashed onto the floor. Kurumi, in her UNIPF combat fatigues, emerged from the ventilation shaft. "Terminal Dogma is off-limits, my ass."
- Nobody Dies: Rei's favorite method of Stealth Hi/Bye is to drop out of any ventilation system. Later revealed to be a trait common to all Lilith-based Nephilem, as when Shinji is temporarily turned into a Nephilem, he suddenly gets good at zipping through vents too. Kensuke is picking it up as well, due to his... "friendship" with Rei.
- Rise of the Minisukas: The titular Minisukas sneak into and out of places by crawling through the air vents. Justified, since they are only eight inches tall.
- The Second Try: Shinji uses a ventilation shaft to sneak out and back in NERV in the second-to-last chapter.
- There are two instances in Pokémon Reset Bloodlines. Both of them are justified given that they involve relatively small Pokémon:
- The first, Ash's Aipom sneaks aboard the vents in Hunter J's airship, opening the doors for Ash and the others to get through to escape.
- The second, Ash's Snivy gets away from the Samurai by sneaking through the air vents of the battle club, and eventually seeing Ash and deciding to challenge him to see if he's the trainer she's looking for.
- Used in Test of Humanity, though it's more of an "incinerator exhaust pipe escape". Subverted in that Wheatley is too fat to fit all the way through and ends up stuck, causing the pipe to explode from the built-up pressure.
- Lampshaded in Later, Traitor. While exploring Maloof's mental world in chapter 18, Frazie and Lili end up crawling through air vents to get at a Memory Vault Maloof has hidden away. Lili points out how air vents big enough to crawl through are highly unlikely in the real world, and Frazie chalks it up to Maloof internalizing the trope from watching too many crime movies.
- In Spice Girls AU Fic, Astral Journey: It's Complicated, after getting sectioned, Melanie does this "twice". Her second attempts ends in disaster, leading to getting injured for real.
- Averted in The Keys Stand Alone: The Soft World. George talks about maybe navigating the air ducts to get to Mevaryat's basement room in the concert hall, but he isn't thrilled about the idea because he has no idea where the things go, and can't really navigate the larger world when he's something small anyway. Later, he finds out that the Tipaanese anticipated he might go in that way and set traps throughout the air ducts. Too bad for them he found a different way to get into the room.
- Epic: The Third Survivor: Sherry spends several chapters roaming around the police station's ventilation system to evade the zombies.
- Sailor Moon: Legends of Lightstorm: In an attempt to bond with Sailor Mercury, Sailor Jupiter suggests that they get into a suspicious building by crawling in through the vents "like in the movies". Misunderstanding her intent, Mercury merely points out that the vents are probably too small for them to fit through.
- In Scribblings, Chloe and Rush both make use of a variant of this: Chloe turns it into a prison for Eli and Rush turns it into a nest.
- In Smash Generation, this is how Midna went to see who was in the Mansion, and also how Pear, Riley, BJ and Popo evaded escape.
- Exploited in Legacy Of The Magi: All Fine Labs has a modest network of easily-traversed vents… that both are monitored and don't actually lead anywhere important, thus getting would-be snoopers to waste their time while also alerting the security team that there are snoopers afoot. This actually comes back to bite them when a memoryhead escapes a room via these vents.
- In All Guardsmen Party the Occurrence Border has plenty such passageways. When Sarge tries looking for similarly-size vents on a properly-built space station, he's told nobody would ever build vents large enough to crawl through. The only reason the Border has such vents is because it's a very stupid ship.
- Used by the protagonists of Yu-Gi-Oh! Forever during the last part of the Dueltropolis arc, to sneak on board the ARK.
