Ballroom Blitz

""And the man at the back said, 'Everyone attack!' And it turned into a ballroom blitz. And the girl in the corner said: 'Boy, I wanna warn ya, It'll turn into a ballroom blitz.'""

- Sweet (or Crucial Taunt), "Ballroom Blitz"

For whatever reason there's a dance or a dinner, or a party of some kind, going on -- be it a snooty royal or noble ball, a school dance or a wedding, or maybe a particularly large birthday party. If it's a more formal occasion, pretty much everyone is dressed up. There's a fairly good chance that if our heroes have been invited, the Big Bad or his Mooks are quite likely to invite themselves; be assured something catastrophic and violent is going to occur, usually in the vicinity of either the entrance or the dance floor. In most circumstances everyone will be unarmed, except maybe the guards (if they even have them). Cue panicked screams, and the Action Girl complaining about having to fight in a dress... until she rips the hem off. May overlap with A Fete Worse Than Death -- or, in a comedy, Hilarity Ensues.

Anime and Manga

 * Soul Eater has this in an episode when Death City is attacked and  during a party celebrating the DWMA's anniversary.
 * Mai's arc in Kanon at the prom.
 * An early episode of Gundam Wing had Lady Une try to assassinate Relena during a school formal, which lead to Heero going out and fighting them off in his Gundam. No fighting actually occurs inside the party, though.
 * In the manga version of Mahou Sensei Negima, Unfortunately,
 * Yu-Gi-Oh! 5D's: Some duelist on a giant spiked bulldozer crashes some fancy party during the WRGP Arc. Aki ends up summoning her dragon and tossing him through a window.
 * Towards the end of the Baccano!! arc set in 1930, at the party to celebrate Firo's entry into the Camorra. Machine-gunning ensues.
 * In Berserk the gang go to see Farnese while she was at a ball. This being Berserk though hilarity ensued. Cute little kitties break into the Ballroom filled with nobles fighting against Emperor Ganishka.
 * In The Big O, Roger gets invited to a masquerade ball and is given a mask to wear. Roger chooses not to put it on--good thing too, because Schwartzwald had booby-trapped the masks to spontaneously combust, turning all of the other attendants' faces, all of them high society people, into charred messes.

Fan Fiction

 * In Naruto Veangance Revelaitons, while Ronan and Sakura are attending the "sibone ball," Madara attacks. Ronan defeats him by mind controlling the attendees.

Film
"Riddler: Your entrance was good; his was better. The difference? Showmanship."
 * In Night of the Creeps, the dance never happened because the busload of fratboys all died due to the eponymous monsters and the undead serial killer.
 * The big fancy ball in Enchanted gets interrupted due to Nerissa first pulling the poison apple thing on Giselle, and then turning into a dragon. Also makes use of All Part of the Show.
 * Carrie is (in)famous for the mayhem that started from a prank that kills the date of the title character with Psychic Powers.
 * Averted in West Side Story, where there is racial tension at the dance, but the gangs wait till afterward to rumble.
 * Prom Night: This was pretty much the whole plot.
 * Buffy the Vampire Slayer: The original film version culminated in an attack on the prom by the vampire hordes.
 * In Blazing Saddles, the Final Battle busts right out of the movie and into the studio next door, where a rehearsal for a dance number is taking place.
 * Collateral: Dragged out rather ridiculously when Max starts shooting in a nightclub to cause a diversion. It works, everyone starts running for the exits... and five minutes later, they're still running. Best hope there's never a fire in that place...
 * Terminator: The Tech Noir club gets blitzed. Luckily Kyle was able to "Zero" the T-800 as a result.
 * Batman villains love this trope :
 * Batman Returns: The fancy costume party at which Bruce and Selina discover each other's identities gets interrupted explosively by the Penguin.
 * Batman Forever: Two-Face crashes Edward Nygma's (The Riddler's) party despite the two working together. Followed soon after by Batman.


 * Batman and Robin: Bruce organizes a charity auction sale of diamonds in order to lure Mr. Freeze. Poison Ivy infiltrates the party in a pink gorilla costume, takes it off and seduces everybody with her love perfume, then Freeze crashes the party.
 * Batman Begins: Rā's al Ghūl breaks into Bruce's party.
 * The Dark Knight: The Joker breaks into Bruce's party. This is why Bruce can't have nice things.
 * Van Helsing: The All Hallow's Eve Ball, which quickly erupts into a battle with Dracula.
 * In Swing Kids, one swing dance party gets raided by the Hitler Jugend, leading to pandemonium as everyone tries to escape out the back. At the end of the movie, the Hitler Jugend raid another swing party, this time more prepared to apprehend everyone there. It does not end well for the partygoers.
 * Daywatch has Yegor's birthday party, organised by the Big Bad and attended by many high ranking Others (and several Russian celebrities in Cameo). Everything goes well, if tense, until Yegor's estranged father, Anton, bumps into a Witch he arrested years ago. A scuffle erupts, turns increasingly violent and climaxes with someone throwing a magical frag grenade that destroys Moscow.

Literature

 * In The Silmarillion, Morgoth attacked Valinor and seized the Silmarils during a festival. Gondolin also fell during a festival when none of the walls were manned.
 * Added to the Dances and Balls of Pride and Prejudice And Zombies, natch.
 * The Red Wedding in A Song of Ice and Fire.
 * In Cluster Command the second book of David Drake's Crisis of Empire trilogy protagonist General Merikur and his wife Beth find themselves in the middle of such a blitz at the welcome ball for the new system governor.
 * The Dresden Files book Grave Peril has Harry winding up attending large party being thrown by a vampire. It winds up being an example of why villains request his presence at their own peril.
 * The Bartimaeus Trilogy: The climax of the first book.
 * Discworld
 * Nanny Ogg's Cookbook: "The Fight" is listed as part of a proper wedding. The last step is "Then the bride cuts the cake."
 * Night Watch: The Patrician's party. Though no actual violence is employed (save for two guards who took crossbow bolts); the Patrician (Lord Winder) is literally scared to death by a young Havelock Vetinari.
 * In By the Sword, Kerowyn is first thrust into her role as Action Girl when mercenaries ransack her brother's wedding, kill her father, and abduct the bride.
 * Bill and Fleur's wedding in Harry Potter and The Deathly Hallows

Live Action TV

 * Minute Men has a dance interrupted by a black hole.
 * Heroes has Claire's big homecoming dance interrupted due to a Sylar attack.
 * In Firefly, Mal inadvertently challenges Atherton Wing to a duel at a shiny ballroom shindig.
 * In the Doctor Who two parter "Human Nature/The Family of Blood" a nice village dance is interrupted by (what else?) an Alien Invasion.
 * In Community episode Pascal's Triangle Revisited an end of the year school dance turns into one of these when Chang attacks Duncan.
 * In Merlin the two-part finale of series four begins when Morgana and her mercenary army attacks Camelot during the Beltane celebrations.

Music

 * The Trope Namer is "Ballroom Blitz" by Sweet. It is a surreal and lighthearted description of such an event. Covered by lots of people: The Rezillos, The Damned, and by Tia Carrere on the Wayne's World soundtrack.
 * It was actually inspired by a gig gone wrong in Scotland in 1973, when the band was showered by bottles from the audience and had to leave before finishing the set ("And the band started leavin'/'Cause they all stopped breathin'").
 * The Julie Brown Song "(Everybody Run) The Homecoming Queen's Got A Gun" involves an interrupted homecoming parade.
 * The Irish folk song "Lanigan's Ball" (given a Boston twist by the Dropkick Murphys as "Flannigan's Ball") is about one of these.

Theater

 * Phantom of the Opera: The Masquerade Ball is, um...gliding right along until the Phantom decides to pay a call...

Video Games

 * BioShock (series): The attack on the Kashmir Restaurant's 1959 Masquerade Ball by Atlas and his rebels just before the events of the game.
 * Castlevania: Aria of Sorrow has a ballroom where you must evade and fight dancing Victorian-era ghosts.
 * The Karazhan raid instance in World of Warcraft has a variation. One section of the dungeon involves going through the ballroom and dining room, which are filled with ghosts. The ghosts are acting as people normally would, dancing and eating, with servants walking among the tables in the dining room. Of course, the players have to fight these ghosts to continue.
 * One mission in Assassin's Creed: Brotherhood turns into this. A Borgia cardinal is throwing one hell of a party, only for Ezio Auditore da Firenze to crash the party and murder the cardinal. Subverted in that all of the guests make it out just fine. The guards, on the other hand, are pretty much boned.
 * The Justified Tutorial of the From Russia with Love game is a cocktail party variant.
 * Occurs at a cocktail party in Tomb Raider Legend, complete with Action Dress Rip.
 * The Banquet Hall level in Die Hard Trilogy 2: Viva Las Vegas.

Western Animation

 * American Dragon: Jake Long had a dance he never made it to because he had to stop the Huntsclan.
 * Ben 10 Alien Force Kevin and Gwen go to a dance, but it gets interrupted by this trope.
 * Kim Possible had it happen to her in The Movie.
 * The first episode of Freakazoid, "The Dance Of Doom" has a high-school dance interrupted by Cave Guy, who takes several of the high-schoolers hostage. Of course, this being Freakazoid, the dance is in honor of Daylight Savings Time.
 * An episode of Teen Titans in which Robin is forced to take a supervillain's daughter to her prom ends up this way when Starfire's jealousy flares up and said supervillain's daughter's ex-boyfriend (who turns into just plain her boyfriend again shortly before the actual Blitz part of it starts) shows up.
 * Danny Phantom: In the second episode, Danny decides to take some inconspicuous ghost-fighting weaponry to the school dance "just in case." Case happens.
 * In The Spectacular Spider-Man, Spidey met the Green Goblin during one of these. It quickly turned into an Enemy Mine, since Tombstone didn't take kindly to the Goblin attacking his guests. (Tombstone is a Villain with Good Publicity and very commited to keeping it that way.)
 * American Dad: In "Haylias", after Hayley's arranged marriage is consummated, she attempts to murder Stan during the wedding party. Notably, one of the scenes, seen just before they start fighting, is a Shout-Out to the aforementioned Carrie.
 * In the X-Men: Evolution episode "Shadow Dance", where the monsters that inhabit the pocket dimension Nightcrawler crosses every time he bamfs from one place to another manage to escape and start making a rampage in Bayville High, during the Sadie Hawkins dance night. Being this the school that the X-Men and the Brotherhood attend, they have no problem dealing with them. Kurt, on the other hand, is afraid of doing anything, both because said monsters had traumatized him earlier on (to a point he swore to himself he would never teleport again) and because he didn't want Amanda to find out he was a mutant.
 * The first Season Finale of My Little Pony Friendship Is Magic, "The Best Night Ever", ends with the Mane cast going to the Grand Galloping Gala... and making a huge mess of Princess Celestia's castle in the process.
 * This happens again in the season 2 episode "Sweet and Elite", when the main cast invite themselves to a garden party Rarity had been secretly attending. Fortunately, the end result is somewhat more positive this time around.
 * In fact, the first example arguably happens right in the two-part pilot with Nightmare Moon crashing Ponyville's Summer Sun Celebration.
 * It happens yet again in the second season finale, when a wedding between Princess Cadance and Shining Armor is interrupted by Twilight Sparkle.
 * Averted in Re Boot. For Enzo's birthday, a surprise party/talent show is planned. Villain Megabyte keeps menacing Bob during the preparations. At the actual party, after the comedy acts, Dot singing a torch song, and other festivities, Megabyte barges onstage -- with an electric guitar. He plays power chords while his dimwit sidekicks Hack and Slash back him up on drums. Bob pulls out HIS guitar, and the two jam with each other! Megabyte's actual plan? "I've always wanted to do that!" He gives his guitar to the birthday boy, gets in his limo, and leaves.

Webcomics

 * Archipelago: Book 6, Snow and the Ravens attack Quillotia Castle during a royal ball. As far as King Mikel is concerned, this does not ruin the evening.
 * RPG World contains one of these in

Web Original

 * In The Gamers Alliance, the Maar Sulais court has a grand ball in honour of the Grand Alliance army which has come to join them in the fight against the Proninist Party. However, just when festivities are about to reach their peak, the Nightstalkers gang crashes the ball in the citadel, causes general havoc and kidnaps the elven mage Tiyana before the heroes can stop them.
 * The Gungan Council has frequent dances and balls, so the Sith decided to host their own called "The Homecoming Ball" and invite Jedi and Rebels. Nowadays, its nickname "The Blood Ball" is known much more than its true name.

Other
"Q: "Why are the floors of dance halls in Ostrobothnia built to have a slope?" A: "So that the blood will run off better.""
 * There is a joke in Finland about the stereotypically stern, quickly aggravated, knife-wielding Ostrobothnians.

Real Life

 * When people objected to weddings in the Middle Ages, it was not unusual for it to end violently. Hence, the title of "Best Man" usually referred not only to trust or friendship, but fighting ability as well.
 * In certain remote rural districts, this tradition has allegedly persisted into the modern age.

It's, it's a ballroom blitz! It's, it's a ballroom blitz! It's, it's, a ballroom blitz! Yeah! It's a ballroom blitz!