Collapsing Lair

"" Just once, I wish the villain's lair didn't have to blow up!""

- Kim, Kim Possible

Inevitably, once the Big Bad (and sometimes even The Dragon) is defeated, his Supervillain Lair (castle, secret headquarters, cave, etc.) will begin to destroy itself, triggering a Chase Scene where the heroes are chased out by the threat of falling rocks, timbers, masonry, etc. and whatever else is collapsing down upon them.

This may be due to a Self-Destruct Mechanism, or due to the lair having No Ontological Inertia. Alternately, the hero's goal may been to deliberately cause (read: destroy) the Collapsing Lair, like by setting off a Time Bomb or pushing the Big Red Button that is invariably linked to said Self-Destruct Mechanism. Or perhaps the combination of the Big Bad's No-Holds-Barred Beatdown and the hero's own Heroic Second Wind resulted in extensive damage to the lair's supports/foundations/whatever, and it was going to start coming down anyway. (When this happens in Video Game form, we call it a Load-Bearing Boss.)

Why is this useful, apart from topping the Final Battle with an exciting escape scene to safety (after which you can directly cut to the happy end celebrations?) Think about it. The Big Bad has had a massive base, with several valuable gadgets, and many remaining lesser minions. You definitely do not want to drag out the story by having the hero deal with them one by one too, and much less to put his hands on something that could change the status quo. Better just blow it all up. And best of all, once you do actually make it out alive, you get the immensely satisfying shot of the hero looking on as the Supervillain Lair goes bye-bye in spectacular fashion.

Often occurs after defeating the Monster of the Week.

If it truly does become impossible to escape the Collapsing Lair, expect to see a Load-Bearing Hero save the day.

Rare in television except as the end of a Story Arc, because destroying sets is expensive: you just have to build new ones next week. In animation, however, it's easy. In video games (as already mentioned), this often happens because of a Load-Bearing Boss.

Anime and Manga
"Kristian Danchecker: I can't believe there's such a clichéd trap at the end!"
 * In Naruto, during the spinoff Kakashi Gaiden in which we learn of Kakashi's childhood, Kakko causes the cave Kakashi, Obito and Rin were fighting him in to collapse in a last-ditch effort to defeat them, resulting in.
 * In the Pocket Monsters (Pokémon) manga, Red and Green set Team Rocket's headquarters on fire. After Red, Green, and Blue defeat Natsume, the building collapses.
 * In Pokémon Diamond and Pearl Adventure, Jupiter blows up the Galactic base to prevent their secrets from getting out. But since this happens in volume 5 of an 8 volume series, when next we return to Veilstone, has rebuilt it to be what it was in the Platinum version of the game.
 * In the Pokémon anime, Mewtwo blows up the Team Rocket base in the beginning of the first movie. The only known survivors are Giovanni and his signature pokémon (there could be more, but they're never addressed either way).
 * Actually, when Mewtwo's flight from the HQ is seen in the show, all that's wrecked is the arena area, and those get trashed on a regular basis.
 * A Baoa Qu at the climax of Mobile Suit Gundam doesn't quite collapse, but there's enough Stuff Blowing Up by the end that the effect is the same.
 * In Magical Girl Lyrical Nanoha (season 1), the Time Garden collapses on itself as a result of Precia's failed Explosive Overclocking attempt to open a gate to Alhazred.
 * In Yu Yu Hakusho, Sakyo, Season Two's Big Bad,.
 * Witch Hunter Robin :
 * Parodied in Iono the Fanatics. The reason why the sorta antagonist's base did the traditional collapse? The building was raised against Japan's building standard acts (it was, for example, leaning) and that's the reason why nobody else was using it even though it looked brand new. Naturally, the high-level battle between the assassin and Iono's bodyguards at the ground-level proved to be a wee-bit too much for its already unstable structure.
 * In Mahou Sensei Negima, after Negi's group is, we first see Nodoka escaping from one of these while treasure hunting.


 * R.O.D the TV has the Dokusensha building and, evidently,
 * At the climax of the Outlanders manga,  ''the entire imperial planet blows up.
 * Digimon Adventure 's Dark Masters Arc had of course the Dark Master whom once destroyed had their chunk of the Digital World which they bastardized destroy and reconfigure itself back to it's original form.This caused the Digi Destined to constantly shift from place to place until finally falling into a dark void filled by Apocalymon after defeating the last Dark Master.
 * Yu-Gi-Oh! gives us Seto Kaiba and his Battle Tower; after the finals, he blows it up! But just a few episodes before that, we have Gozaburo Kaiba, who triggers a meltdown so our heroes can't escape.
 * The Halcon research facility falls apart at the end of Appleseed Ex Machina for no apparent reason, other than to fulfill the cliché. In fact, it has no other reason even to exist!
 * The dungeons in Magi Labyrinth of Magic collapse after they have been successfully completed.

Comic Books

 * Blue Mountain in Elf Quest is completely destroyed at the end of the aptly-named "Siege at Blue Mountain" arc, but not before.
 * Subverted in All Fall Down: The Order of Despots' Supervillain Lair on the Moon is still intact and fully operational two years later.

Fan Works

 * Parodied in Harry Potter and the Evil Summer Vacation, where Harry accidentally ended up at a conference for aspiring criminal masterminds. The (mandatory) final seminar on the last day of the conference was "Secret Lairs, Part 3 - Defenses, Escapes, and Self Destructs". After an agent from SPECTRE gave a talk on why it was important to set up a new lair for every plan and how you should try to take out both the evidence and the good guys as well as your headquarters, they evacuated the conference theater and then blew up the hotel where it was located.

Film

 * All the Indiana Jones movies have a large building getting destroyed (Raiders of the Lost Ark has part of the Chachapoyan temple, Temple of Doom has the mine, The Last Crusade has the inside of the Grail Temple, and Indiana Jones and the Kingdom of the Crystal Skull, the entire city of Akator).
 * In the horror film Suspiria, after the head witch stabbed, not only are all the other witches seen rolling around on the floor clutching at invisible neck wounds, but the whole ballet school tears itself apart, with furniture flinging itself through windows, walls cracking, beams falling and unlikely objects, such as statues and door knobs, simply exploding for no good reason. When Susan walks away at the end, the whole place is on fire.
 * The destruction of the enemy mothership in Independence Day with a tactical nuclear missile with a 30 second timer.
 * A self-activating Self-Destruct Mechanism destroys Sir August de Wynter's island lair at the end of The Avengers 1998.
 * At the end of Forbidden Planet, the hero throws a switch that will cause a chain reaction in the Krell furnaces that will destroy the planet Altair-4 in 24 hours.
 * Our Man Flint. Derek Flint's sabotage blows up the enemy base on Galaxy island.
 * The Allied saboteurs trick the Germans into blowing up their own base (and the title weapons) in The Guns of Navarone.
 * Logan's Run (1976): Logan's destruction of the tyrannical central computer causes his city to blow up, freeing its people.
 * Phantasm: The Tall Man's mortuary has a gate to his home planet. When Reggie grabs both columns of the gate at the same time, it's destabilized and eventually destroys the whole building.
 * At the end of Beneath the Planet of the Apes, a cobalt bomb in an underground mutant lair is detonated and wipes out not only the lair, but all Earth (NOTE: This was detonated by Col. Taylor himself—which is ironic, since he cursed mankind for doing the same in the original "Planet of the Apes" (famous "Statue of Liberty ruins" scene).
 * The Mummy 1999 ends with a temple collapsing after Benny accidentally activates the "sink into sand" system. The Mummy Returns ends with an oasis and the pyramid it houses vanishing into the desert, but due to Load-Bearing Boss.
 * Let us not forget in Conan The Destroyer, an entire tower collapses shortly after the wizard's death with one character giving the hand-waved explanation, "It was all an illusion."
 * Many James Bond movies end with Bond escaping from the villain's Collapsing Lair.
 * Dr. No, You Only Live Twice, Diamonds Are Forever, The Man with the Golden Gun, The Spy Who Loved Me, Moonraker
 * Alien 3 was the only time Ellen Ripley didn't destroy everything as she left. Ron Perlman's character says it "must be a chick thing".
 * The Jungle Book features this occurance when Baloo & Bagheera fight the band of monkeys over Mowgli. Justified because of all the damage the ruined city endures during the squabble, with several pillars being destroyed.
 * The end of Congo results in the convenient destruction of the "evil" gorillas' lair via volcanic eruption...despite the fact that it had been standing for hundreds of years before the protagonists got there.
 * In a variant, the house from Poltergeist collapses in on itself, and is apparently sucked into another dimension, at the end. The resident ghosts weren't actually destroyed, but were "defeated" in the sense that the whole family escaped alive, despite everything the evil presence could throw at them.

Literature

 * Barad-dûr or The Dark Tower from the The Lord of the Rings was over two thousand feet tall (some sources suggest over 4000!) and was held up by Sauron's disregard of structural physics. Naturally, with the destruction of The One Ring and Sauron's demise, the tower came toppling down. Peter Jackson's interpretation, in the film, made it even more extreme,
 * Well, even in the original work the Black Gate fell at the same time as the Dark Tower. The explanation given was that Barad-Dûr's foundations and the Gate had been built with the power of the Ring, and it actively held them together, but disregarded the timeline in which the Tower was built before the Ring was forged, and the Gate was built by Númenóreans, not Sauron, to keep the evil creatures inhabiting the country inside.
 * Sauron could have done some remodeling...
 * The tower was originally built without the Ring, but it was built by Sauron's power (as opposed to mortal carpenters and masons and the like), and it was later rebuilt again by that same power. When Sauron crafted the Ring, he put much of his personal power into it, at which point the tower's continued existence became tied to the Ring. It's explicitly mentioned at one point that the only thing still holding the tower up is Sauron's power - and when the One Ring was destroyed, ALL of Sauron's power was lost... which included the power holding the tower together. As for the the Black Gate, it was built by Sauron (not the Númenóreans) around the same time he built Barad-Dûr, so we can easily assume it was built via the same means (thus making it vulnerable to the same doom).
 * The Towers of the Teeth, which were the towers on either side of the Black Gate, WERE built by the Númenóreans (they were to be guard towers over the entrance to Mordor, just like Cirith Ungol and Minas Ithil/Morgul). After Sauron took back his territory he captured all of the man-built towers and used them as his own. He then built the Black Gate between the Towers of the Teeth to fortify his lands.
 * In C. S. Lewis' The Silver Chair, the witch has spells to collapse her realm once she is dead. This is in some ways a good thing,
 * It's implied that she purposely wove these spells into the cavern so that nobody could kill her without likely meeting their own demise soon afterward.
 * The collapse of the titular house at the climax of Poe's 1839 story The Fall of the House of Usher makes this Older Than Radio.
 * King Haggard's castle collapses dramatically at the end of The Last Unicorn. Given that the book was a loving spoof of fantasy tropes itself, this is not surprising.
 * The collapse was supposed to be triggered by.
 * In Captain Underpants, the spaceship self-destructs.
 * In the Conan story "The Tower of the Elephant," when Yag-kosha takes his revenge upon the sorcerer Yara by way of Conan, the titular tower, which Yag-kosha built for him in a single night, shatters into a million pieces after Conan escapes.
 * In Stephen King's IT this happens on a rather large scale.
 * Not exactly;
 * In Dan Abnett's Gaunt's Ghosts novel First & Only, when the Inquisitor Heldane's pawn is killed, the psychic shock kills Heldane as well, and his unleashed psychic energies tore apart the spaceship he was one. Good thing for the Ghosts and their allies that Heldane used the pawn at a distance.
 * In Tad Williams' Memory, Sorrow and Thorn series, the shock of the Storm King's destruction causes Green Angel Tower to collapse with the protagonists inside, naturally prompting an escape scene. Some make it out, some don't. The story makes it somewhat ambiguous whether this is a case of No Ontological Inertia or the aftereffects of the spell that summoned him, but it's striking that Green Angel Tower was the sole remaining Sithi structure in the Hayholt and the exact place where Ineluki killed himself 500 years prior, becoming the Storm King. To be fair, the series' Functional Magic is explicitly stated to work on the principle of No Ontological Inertia.
 * This trope turns nasty in Guard Against Dishonor, from Simon R. Green's Hawk And Fisher series. As per tradition, the pocket dimension in which a deadly new drug is being prepared fails when the sorcerer that created it is killed by the Watch; untraditionally, this has worse consequences than just a dramatic race for the exit, as the pocket's collapse takes a crowded city tenement down with it, causing hundreds of civilian casualties.
 * Happens quite frequently to The Lonely Winds, usually as a result of Marc doing something stupid. Lampshaded by Nails in The Absolution: "...why does every single fight we get into end with something on fire?"
 * Parodied in Feet of Clay, when freelance exterminator Wee Mad Arthur explains why he charges so much more for disposal of wasp nests. Being a gnome only a few inches tall, he plants squibs inside the nests and then has to fight his way to the exit before they blow.
 * Also done straight in The Colour of Magic.
 * There are three of these in the Prydain Chronicles.
 * In Christopher Stasheff's Her Majesty's Wizard, after the main character recited a Shakespeare passage about the banishing of illusions, the castle of the lust witch Sayeesa faded into thin air, leaving only an empty crater and a number of no-longer-enthralled young men and women.

Live-Action TV

 * In the final episode of Buffy the Vampire Slayer, Sunnydale itself is a Collapsing Lair.
 * And so is the Wolfram & Hart office building in the final episode of Angel.
 * As well as the following home bases: The school library (Buffy season 3), Angel's office (Angel S1), the magic shop (Buffy S6). And for the villains: the factory (Buffy S2), the Initiative (Buffy S4), and the original Wolfram & Hart building (Angel S4).
 * In the Pilot of the original Battlestar Galactica, the planet explodes as the human fleet is fleeing, thus destroying the Cylon basestar which was very close to the surface. The reason? They set fire to a fuel deposit.

Video Games

 * Portal. After you, the room you're in blows up, and you end up outside the Center.
 * See Load-Bearing Boss
 * Tomb Raider 1, 2, Legend and Anniversary.
 * Where in Legend did this happen? Also, Tomb Raider 4, at the end, with Lara apparently falling to her death.
 * I think he's referencing the flashback sequence where, and the entire tomb collapses in on itself. You then proceed to return and attempt to drain it.
 * One of the three endings of Deus Ex involves the player blowing up an Elaborate Underground Base. The final cutscene is unclear on whether or not he makes it out alive.
 * Metroid games often contain segments (especially at the end) where the player must guide Samus out of one of these before a timer runs out.
 * Whenever Dracula is defeated, Castlevania will collapse, leaving only ruins. The protagonist, especially if he is a Belmont, will usually watch this from a cliff.
 * This case is, however, justified: Castlevania is a creature of Chaos (that's why it looks different in every game), held together by Dracula's power.
 * Sly 3: Honor Among Thieves
 * Ico
 * Lampshade hung in Swordcraft Story 2, where an NPC is trying to make the protagonist get something she lost without being obvious. So she tells her that the sword the protagonist is trying to get will cause the cave to collapse without the object. Another character on the scene remarks, "Ah, the load-bearing treasure!"
 * Can't forget The Legend of Zelda Ocarina of Time, after defeating Ganondorf. Made cooler by the fact that you get to fight Ganon on the wreckage. Made slightly more annoying by the Iron Knuckles and ReDead that like to paralyze you while the timer ticks down.
 * Neverwinter Nights 2 - It's even Lampshaded in the first add on pack.
 * Might and Magic IV ends with this, although the party does get out safely.
 * In Strong Bads Cool Game for Attractive People, Homestar Runner literally says that Trogdor "must've been a load bearing dragon".
 * Half Life 2: Episode 1 is sorta this. In a nutshell it involves going into the citadel to slow the timer(conveniently sped up by the combine) then getting the hell out of dodge before it does, making all of C-17 the Collapsing Lair.
 * In the Roguelike game Nethack, if there's an unrecoverable bug in the game, the dungeon collapses, and you lose the game, having "panicked"
 * Fallout: Fallout 1 had two cases of bases with nuclear self destruct devices (I guess the megalomaniacal bad guys wanted to make sure their plans would fail if they happened to die?). Fallout 2 had at least one, sabotaging the computer that keeps the nuclear reactor from exploding. Fallout 3 has a base that can be convinced to blow itself up, and in a DLC a mobile base that controls a Kill Sat that can command the kill sat to target the base itself.
 * Descent: Every level was ended with blowing everything up and having to fly back to the emergency exit for a dramatic just-in-time escape.
 * Every endgame location in every Resident Evil ever made. Sometimes this even happens twice, as in Code Veronica.
 * Revenge of Meta Knight ends with the Halberd breaking down and Kirby fleeing on a Wheelie, while Meta Knight attempt to slow him down and keep him from escaping.
 * Vampire: The Masquerade Bloodlines: Bloodlines had one near the end of the game, in the form of Vampire Hunter Grunfend Bach, who, after being beaten by the player, waits to greet you on your way out with a detonator.
 * The island in the original Devil May Cry begins to fall apart when Mundus does.
 * Marvel Ultimate Alliance 2 has a sequence very early in the game where the player's squad of four heroes must escape Castle Doom as it implodes, occasionally dropping large chunks of its innards onto the player's heroes as they go.
 * The Elder Scrolls Oblivion: The Shivering Isles expansion requires you to escape one of these, while boulders fall as if the DM is mad at you.
 * Mega Man: This happens to Skull Castle very often at the end of games in the original series.
 * In The Godfather: The Game, you have to raid enemy compounds and sometimes their businesses, leave a Time Bomb at a specific spot and leave. If you succeed in escaping the place before the bomb goes, you get to see flames on the (temporarily) out-of-commission building.
 * Happens several times in Wolfenstein 2009. The massive underground base in the caverns beneath the farm explodes after retrieving a crystal being used for research deep within. Later, the entire Cannery explodes after defeating a certain load-bearing boss (though this was a result of destroying several critical pieces of machinery, rather than the boss's death). It also happens at the end of the game, after defeating the last boss.
 * Occurs in the Templar Archives after Altaïr kills Armand Bouchart in Assassin's Creed: Bloodlines.
 * Unreal: After killing the final boss, although not so much collapsing as exploding while you run for the escape rocket.
 * An early example could be found in the Atari 8-bit game Caverns of Mars from 1981. After reaching a reactor in the cavern, the player sets it off and must escape before it explodes.
 * in Professor Layton and the Unwound Future.
 * Bionic Commando: "This base will explod in 60 sec", after killing Master D.
 * The Final Fantasy games are no stranger to this trope.
 * Final Fantasy II and Final Fantasy XII have airship bases that get blown to pieces.
 * Final Fantasy IV has
 * Final Fantasy VI has
 * Medal of Honor: Allied Assault has you demolish Fort Schmerzen in the final level by detonating a gas main, and run for the exit while it's being rocked by explosions.
 * At the end of Halo 3, the activation of the unfinished replacement ring causes it to shake itself apart, and you have to drive across the crumbling superstructure.
 * In Alpha Protocol, the Grand Finale takes place as the Alpha Protocol base is being "sanitized" in preparation for the agency closing its doors and opening up shop somewhere else under a new name. This process has less to do with paper shredders and more to do with time bombs. As you proceed through each section of the base, the bombs in the previous sections go off, cutting you off from going back the way you came.

Theatre

 * At the end of Tanz der Vampire this happens to the castle of Count Krolock - for no goddamn reason as we aren't even shown if he died or not. Which is, given the Fridge Logic of the play, not even likely.

Web Animation

 * Parodied in the Strong Bad Email the paper: "How is this island sinking? I didn't even kill any end bosses!"

Web Comics
"Ms. Proctor: That's it? That's your final showdown? Seems pretty anti-climactic to me. [...] Dr. Eldritch: I suppose it would feel more complete if your fortress collapsed on our way out. Zastro: Only if I can collect on the insurance! (both): Hahahahaha!"
 * At the end of the "Dangerous Days" arc in Sluggy Freelance, the building Hereti Corp set the building they had used for the Aylee project to self-destruct. This is apparently standard Hereti Corp procedure for anything they might lose, even bagels.
 * Minions At Work: Well, I see here your last place of employment self-destructed
 * A rare protagonist (sorta?) example comes from Erfworld. After the Coalition forces overwhelm Gobwin Knob and nearly destroy the city, Parson Gotti orders everyone into the caverns, then has their remaining casters link up to use their various magic powers to awaken the dormant volcano beneath the mountain. The resulting explosive eruption wipes out not only the city (which gets fixed soon after), but the entirety of the Coalition forces.
 * The Dungeon of Dorukan collapses after Order of the Stick defeats Xykon and.
 * In Eight Bit Theater, this occurs twice: once when the fiend of fire, Kary, Then, right after   A possible third time occurs in the final boss fight when
 * Happens in Panthera when  destroys the load-bearing columns of the underground facility when he loses his alias and his support, leaving Panthera   in the collapsing room.
 * Mocked in Ask Dr. Eldritch:

Web Original

 * In Sailor Nothing,

Western Animation

 * Pretty much standard for Phineas and Ferb's B Story involving Dr. Doofenshmirtz and Perry the Platypus.
 * Kim Possible, in episode "Downhill", gave us the title quote.
 * And in other episodes, such as the time that Dr. Drakken his his lair inside the world's biggest wheel of cheese. And then built a raygun capable of melting said giant cheese. Hilarity Ensues.
 * Clerks the Animated Series parodied this when Dante and Randal escape from an Indiana Jones and the Temple of Doom-style mine, and Randal stops to pull a lever on the wall marked "do not pull". The entire mountain then begins to collapse.
 * In an episode of The Spectacular Spider-Man showcasing the Sinister Six, Spidey must visit Doc Ock's underwater lair to thwart his plan of world domination. After successfully doing so, Doc hits the self-destruct button, causing a tense moment as Spider-Man must free himself from a large chunk of metal, save Gwen, and get out of the lair all before it blows up.
 * Happens a couple of times in Teen Titans:
 * In "Apprentice II", Slade triggers his lair's self-destruct so that the Titans will be too busy saving themselves to prevent his Villain Exit Stage Left. It works.
 * In "Aftershock II", Terra turns on Slade and unleashes so much power she loses control of it, triggering a volcano beneath the lair. The lair is destroyed and Slade is killed; Terra performs a Heroic Sacrifice to shut the volcano down and keep the damage from spreading further.
 * In "Deception", Cyborg turns new Big Bad Brother Blood's superweapon against him. Blood uses his telekinetic power to keep from being killed, but the unleashed energies cause the lair to begin caving in.
 * In "Wavelength", Brother Blood's new secret weapon is overloaded, destroying his base in the process.
 * In "Titans Together", the Brain tries to set off a bomb to destroy the Titans as he flees his base, but they teleport it away and capture him.
 * Watership Down, the TV series, inverts this as a positive version for the heroes, after Hazel manages to get the other males to do their bit digging their new burrow with the doe, Blackberry. At one point, all the gang is working on one area when the ceiling partially collapses. However, no one is hurt and the rabbits find that the accident cleared away much of the material to create a very nice great hall for their burrow.
 * Dark Heart's lair in Care Bears Movie II: A New Generation, after.