Way to go! The Big Bad's base is gone, his generals have been destroyed, and his Mooks have run away! It looks like you've finally won! Wait a minute, what's that crawling out from under the rubble? Yipes! It's the Big Bad, and he looks as mad as hell! What's this? He's challenging you to a final battle? Prepare yourself for a Last Villain Stand!
This is where the Big Bad has lost his army, his plan has been ruined, and decides to fight the heroes on his own. Usually he uses Applied Phlebotinum or a MacGuffin to take on a One-Winged Angel form and becomes more powerful than ever before.
Usually, this is a desperate play by the villain when he has nothing left to lose, has gone through a Villainous Breakdown, and all that he's driven by now is a mad thirst for revenge for the heroes thwarting his plans to rule the world, the universe, or whatever he was after. He may take things to such an extreme that he doesn't care what happens to him as long as he destroys the good guys. It usually ends with the Big Bad being destroyed and the heroes coming out alive.
There are some cases where this trope is inverted when the Big Bad is a One-Man Army, his one man stand is not so desperate and he's still able to carry out his diabolical plans on his own. If this is the case, the villain is usually defeated when a miracle happens and the heroes gain the power needed to defeat him. This requires a certain amount of Villainous Valor, and if played correctly it may shift the audience's sympathy a bit more toward him.
Unlike a Last Breath Bullet, the villain is still very much alive. However, this can still lead to Taking You with Me. Compare with Last Stand, where it's the heroes who are the ones making the desperate play. Contrast with Villain Exit Stage Left, where the villain flees instead of staying to fight to the end.
Just about every villain in Digimon Adventure has one of these. In fact, the dub version of the episode where Piedmon, the literal Monster Clown, met his destruction was called "Piedmon's Last Jest". Of course, these examples could be considered inversions as they were able to successfully deal with the heroes only to be defeated when one of the members unlocked their digimon's newest evolution, thus giving them the strength to overpower the villains.
Frieza's last shot at Goku, in Dragon Ball Z, certainly counts. Frieza had lost all his minions, failed to obtain immortality, had been demonstrated as not being the strongest in the universe, had even been cut in half (by his own attack, no less), and was only alive because his enemy decided to give him enough energy to survive his injuries. Instead of using that energy to try to escape Namek before it exploded, he tries to kill Goku one last time.
He recovers though, albeit only for a time-traveling Trunks to effortlessly blast him and his father to pieces.
Megatron at the end of Transformers Cybertron. After he loses the Omega Lock, his minions have deserted him, and his plan to reshape the universe to his own desire is foiled, he decides to go all out and ruin the Autobots' plan to save the Jungle Planet for no logical reason while challenging Optimus Prime to a final battle.
And then, after the Big Zam is crippled by the Gundam and about to explode, he walks out in space and shoots the Gundam with an assault rifle. Amuro sees his determination to fight to the end embodied by a demonic spirit, and not only nearly craps himself from the vision, but almost forgot to get the Gundam away from the imminent explosion.
One could argue that the last five episodes of Mobile Suit Zeta Gundam serve as one of these for Big BadPaptimus Scirocco and the Titans as a whole. Outlawed by the Earth Federation, and hunted by the AEUG, with their leadership in tatters, and their superweapons totalled, the Titans ally themselves with Haman Khan (The Big Bad of the next installment, Gundam ZZ, who is planning to use and then discard the Titans) and throw themselves into one last battle with the pursuing AEUG. There is no question in the viewers or the characters' minds at this point that, no matter the outcome of the battle, Scirocco and his followers are going down, whether at the hands of their enemies or their allies. The only question remaining is how many heroes are going down with them? Thanks to Yazan Gable the answer is "most of them."
One Piece does it relatively scarcely, since thwarting the Big Bad's plan typically has Luffy pummeling them enough to kill a normal person. The first Big Bad that actually does it is Gekko Moria of the Shichibukai (Seven Warlords of the Sea); Luffy and his crew have wrecked his base and have just defeated his most powerful monster, and he himself is rather the worse for wear. So, in order to avenge himself upon them, he assimilates the 1,000 shadows he has on the island into his own body, absorbing all of their power and growing into a giant monster. Even in spite of the reduction in speed it gives him, and the fact that it's hard for even him to control that many shadows, it's still an effective One-Winged Angel form considering that the Straw Hats were on the brink of exhaustion.
It's scarce in canon thus far, but there's a non-canon example at the start of the Grand Line saga with Dragon-in-Chief Eric, user of the Kama Kama no Mi (Sickle-Sickle Fruit). He sought out Millennial Dragons in order to obtain dragonite, a substance made from their bones which created the elixir of immortality. When the Straw Hats find the dragons' nest, Eric is ready to reap his rewards, but Luffy ends his hopes by sending him flying as a Twinkle In The Sky. Later, as the pirates are climbing Reverse Mountain, Eric confronts them, having stowed away, and announces his intent to reap Luffy's bounty as compensation for what he had done. Subverted, however, in that before he can fight, Nami pulls a Look Behind You and then knocks him overboard.
The Anti-Monitor, multiple times during the Crisis on Infinite Earths. After his fortress and army get destroyed, he decides it's time to take on all the heroes by himself at the dawn of time. When this partially fails, he gets so angry that he essentially forgets his goal of multiversal conquest and concentrates solely on destroying Earth, slowly and painfully. And when that fails, and the heroes think him defeated, he clings to life through sheer force of will, multiple times, finally fighting a one-on-one duel in a weakened state with the original Superman.
In the prologue of Crossgen's Sojourn, Evil Overlord Mordath's armies and even his entire fortress have all fallen before the hero Ayden and his alliance. Mordath rises up from the rubble wielding his battleaxe demanding that Ayden face him. At this point he knows he has no chance of winning anymore. He just wants to meet the person responsible for his downfall face to face so he can have one good crack at him.
Children of Time has Professor Moriarty making one final play at hurting the heroes and being restored to normal aging. He has the heroine Bound and Gagged and viciously breaksthe Doctorby talking. It ends in three bullets: one from Moriarty to Beth's arm, one from Watson to Moriarty's body, and one from Moriarty to his own brain.
In Equestria: A History Revealed, during the Equestrian Civil War, Princess Luna, upon losing the bulk of her forces at the Battle of Canterlot and knowing the war was lost, pulls this tactic with her remaining forces in the Battle of the Everfree Fields; in order to take down as many of Celestia's ponies with her army as she can.
The Changelings as a whole do this at the climax of the Wedding Arc. With their masquerade broken, most of their higher ups captured, and their brainwashed Slave Mooks/Equine Shields freed, they barricade themselves in Canterlot castle to face down the rebellion started by the Mane Six.
Beauty and the Beast: The Enchanted Christmas has this with Maestro Forte, the court composer who was transformed into an Ominous Pipe Organ with the enchantress's spell. He was Beast's confidant and close friend…but he was also the only resident of the castle who did not want the curse to be broken. To that end, he made every attempt that he could to sabotage Beast's relationship with Belle, while posing as the Beast's friend who only wanted the best for him. But when love eventually overcomes the Beast's bitterness, Forte goes into a Villainous Breakdown, and literally pulls out all the stops, attempting to use the sound waves from his pipes to bring down the whole castle and kill Belle and Beast, stating "They can't fall in love if they're DEAD!"
Forte: So, Beast gets girl and it's a happy ending for everyone. Enchantment lifted, and Forte fades into the background. No longer important. No longer needed. I THINK NOT!
In Kung Fu Panda 2Lord Shen has his entire army destroyed, has killed his own Dragon, and lost everything. When Po finds him on the wreckage of his flagship in the middle of a Villainous Breakdown and offers him a Last-Second Chance, Shen rejects it and does the one thing he'd been running from the entire film, fight Po himself in a final showdown.
In Mulan, Shan Yu after his army was wiped out by an avalanche and his generals have been captured.
He in fact does this twice: after losing most of his army, he and a small band of his most Badass henchmen come very close to victory anyway, and are prevented only by the Emperor's refusal to bow to him and Mulan's quick thinking. Following this, he tries to pull a Taking You with Me, and again comes very close to succeeding.
The Great Mouse Detective: Big Bad Ratigan is utterly and completely defeated and Out-Gambitted - every single one of his options closed off by the heroes. He then resorts to attacking Basil head-on, with the singular intent of killing him.
At the end of The Incredibles, after the Incredibles have defeated the Omnidroid, his plan to be the world's greatest hero is ruined, and he's lost all his resources, Syndrome decides to invade the Incredibles' home and kidnap Jack Jack. Two factors that foiled it were Jack Jack's superpowers manifesting and his Dangerously Genre Savviness not including the concept of a Cape Snag.
Auric Goldfinger escaped the destruction of his base, he cornered Bond and Pussy Galore on a plane to the White House, holding them up with a literal golden gun, only to miss his target and shoot a window before being sucked out of the plane and falling to his death.
His Stealth Yacht was burning but Elliot Carver from Tomorrow Never Dies still had a backup plan. Unfortunately after kicking Bond in the balls and holding him at gunpoint, he felt the need to explain this backup plan, giving Bond time to push him into the path of a whirling propellor thing.
In The Avengers, it becomes clear that Loki's entire plan is this to some extent; he already lost Asgard, the kingdom he actually wanted, in Thor, and so he tries to take the Earth instead, mainly to spite his brother. Before and during the final battle, Tony Stark explains at some length that "there is no version of this where you come out on top", Thor incredulously asks "You think this madness will end with your rule!?" and Loki doesn't actually refute what they say. On the contrary, there are several points throughout the film where it's made very clear that he sees no other option but to keep going, and the audience knows that he is being threatened with A Fate Worse Than Death if he fails to deliver the Tesseract to his mysterious benefactor, Thanos. Essentially, he knows that he'll almost certainly fail, but his pride won't let him surrender without trying every trick he can think of and it takes a hilariously one-sided confrontation with The Incredible Hulk to convince him that he really can't win.
In Iron Man 1, Pepper manages to obtain evidence of Obadiah's villainy and get it to the authorities. Realizing he's screwed, Obadiah snaps and enters the Iron Monger suit in a desperate bid to kill everyone involved. Pepper outright says that he's gone insane.
In Man of Steel, Zod does this when his entire army is sealed in the Phantom Zone with his ship and all of his weapons. He even masters a full set of Kryptonian powers for the fight.
In the climax of Teenage Mutant Ninja Turtles 2: The Secret of the Ooze, the Shredder, defeated and humiliated for the second time, drinks the last vial of mutagen, mutating himself into what Donatello calls a "Super-Shredder", an ogre-sized monster blinded by rage. Determined to crush his foes even if he goes with them he tears the entire pier they're under apart until it collapses; fortunately, the Turtles are able to bail out and survive, and while it looks like the Shredder might make it out too at the end, he does not.
At the end of Serenity, the Operative didn't really need to come after Mal on his own, even if his Alliance support had their hands full fighting the Reavers. And yet, after failing to blow Serenity out of the sky due to said Reavers' arrival, he insisted on following Mal through an obstacle course with his sword.
In The Wolverine, Shingen’s battle with Logan could be interpreted as this, as he has lost everything by that point, and he just throws himself in a battle he can't win.
Sauron at the end of the War of the Last Alliance; after losing most of his forces, he came out himself and faced both opposing leaders (Gil-Galad and Elendil) in a duel. He killed both of them, only to die himself (temporarily) when Elendil's son Isildur cut the One Ring off his hand. Subverted the previous time someone assaulted Sauron's fortress- when he realized that the Númenórean forces were too powerful for him to defeat, he came out to talk, not fight- and he ended up wrapping them around his little finger.
Almost every villain in Redwall has already lost the battle before their final fight with the hero of the book.
Hagen in the ending of the Nibelungenlied, because given that among other things he murdered Siegfried and Kriemhild's and Etzel's infant son, there should be no question that he is a villain.
The first Mistborn book has this, of the One-Man Army variety. Throughout the book, killing the Lord Ruler is treated as the most insane objective of an already impossible-seeming plan to overthrow The Empire. When the final stage of the plan is put into action, Vin meets the Lord Ruler face to face and realizes that yes, he can indeed still kick all their asses singlehandedly. The garrison is mostly absent; what's left has either defected or been defeated; the nobles are all hiding in their keeps if they haven't outright surrendered; and the order of dragons has been destroyed from within. But even as the resistance army Zerg Rushes the palace, the Lord Ruler decries them as beneath his notice. Somehow, Vin has to figure out how to kill him. Cue Final Boss battle.
Septimus Heap: Merrin Meredith's fight against Septimus in the river in Darke can be seen as this, since he's just lost his dragon and the control over the Darke Domaine and has barely anything to lose.
In Power Rangers Lost Galaxy, after Trakeena loses her entire army (though that was because she had them perform kamikaze tactics), her ship is destroyed, and all her minions are gone, she enters the cocoon her father made for her to take on the One-Winged Angel form she was destined for and in an act of pure desperation, powers up the remains of the Terra Venture and attempts to crash it into the planet the colony had flown to in an attempt to destroy them and the Power Rangers. Either she overlooked the fact that she would die too if she succeeded, or else she was just trying to pull a Taking You with Me.
Power Rangers Time Force has Ransik taking a last stand as well. It is inverted when he nearly wipes out the Rangers single-handed - he gets his visor blown off, but it ends up with just him and a demorphed, barely-standing Jen. He's only "defeated" when he attacks his own daughter by mistake, at which point he realizes that being so obsessed with his hatred almost cost him the only one he loved. After that, he surrenders.
Power Rangers Dino Thunder has this as well with Big Bad Mesogog: His minions are gone, his base is destroyed, his plans are ruined, and his Dragon-turned-Starscream's massive Zord failed to defeat the rangers. Mesogog then confronts the rangers, and states that he managed to absorb enough power from their Dino Gems to complete his transfiguration. After saying the line below, he evolves into Mesomonster, a self-replicating and nearly invincible beast. It takes literally everything the rangers have to destroy him.
Mesogog: Witness the face of...your final battle!
In Power Rangers S.P.D., Emperor Gruumm ultimately takes a last stand as well. After his army is destroyed and Omni has fallen, Gruumm erupts from the rubble of Omni's mechnical body and challenges his nemesis Doggie Cruger to one last battle. When Doggie wins, Gruumm orders him to end it, but Doggie refuses, instead cutting his other horn off and arresting him.
Very common in the original Kamen Rider series. Many of the Generals/Commandants/Warlords, whatever they were called in their specific organization, would face down their Rider after he'd slaughtered their armies and ruined their plans enough, transform into a monstrous form with incredible power behind it, and fight the Riders one on one.
Happens by default in Kamen Rider Double, since Big BadJun Kazu/Utopia Dopant didn't actually have any minions or allies, and he's all that's left standing after original Big Bad Ryubee Sonozaki was defeated a couple of episodes before.
On Angel after her brainwashing powers are lost, Jasmine declares that if she can't rule the world she's going to destroy it. She shrugs off everything Angel tries to throw at her, but we don't get to see how she actually intends to accomplish her new goal because Connor, whose immunity to her powers apparently stretched to ignoring her invulnerability, shows up and kills her.
The 9th season finale of Criminal Minds has Preacher Justin Mills do this against the FBI and the local police. It's actually invoked by the Dirty Cops in order to set him up as the killer, but by this point the BAU has deduced he's being set up.
While every Mega Man boss is willing to hop in a mech or whip out a new battle body when you finally confront them, Epsilon of Mega Man X: Command Mission is a little different in that he's fueled not by desperation, but by belief in his ideals and goal. He's also a little different in that he's not the Final Boss.
"I can see you are determined. But Scarface...I will not run from this fight. For I know that this bridge must be crossed to achieve our ideal. They will tremble before the power of...Epsilon!"
Minus the transformation (he did that earlier with some puppets), Ganondorf does the same thing at the end of The Wind Waker as the heavens actually the OCEANS rain down around them and Hyrule is lost to him forever.
And in Twilight Princess, after the Twilight has been purged from Hyrule and is unlikely to return, Zelda has been freed, and Hyrule Castle destroyed, Ganondorf does it again, first on horseback and then on foot.
Regardless of the above pattern, A Link to the Past provides an inversion, as the whole point of rescuing the maidens in the Dark World was to get Link into a position where he could kill Ganon before the latter could escape into the Light World. If the last fight was lost, Ganon would theoretically have been able to proceed with his plan.
Desann in Jedi Outcast still chooses to duke it out with Katarn, despite losing his entire fleet and most of his strike troops having been wiped out by the Jedi. Admittedly he doesn't even know the attack has failed until Kyle tells him just before the fight, and the entire thing was a diversion to get him to the Academy basement where the fight takes place anyway.
By the time you reach Colonel Autumn in Fallout 3, the Enclave has been utterly annihilated by your indestructible 40-foot tall super-robot, and all that's left of Autumn's army is him and his 2 bodyguards. Despite this, he proclaims that "the Enclave is at the height of its power!" and seems suicidally overconfident that he can take you, despite being a massively underpowered Zero-Effort Boss.
Mook example: Behemoth Kings in Final Fantasy XIII start off pretty strong, and when their HP gets down to half, they stand up. But it's when they're at under 10% HP that they're at their most dangerous: they'll start spamming Sunderevery few seconds! If you're not prepared for it, this will kill you then and there. (At this point it's easily enough to one-shot your Medic, and the battle is pretty much Unwinnable from there.)
Araman pulls this in Neverwinter Nights 2: Mask of the Betrayer after you win your Crusade against the Fugue Plane. Considering you've killed him once already, and your party likely consists of four 30th-level characters, this qualifies him as Too Dumb to Live.
Liquid Ocelot in Metal Gear Solid 4. Even after having most of his forces wiped out, from his Metal Gears being destroyed to his elite soldiers being essentially lobotomized after the destruction of the Patriots (long story), he still faces Snake in one final, climactic boss battle atop Outer Haven.
Liquid in Metal Gear Solid is another great example. After losing his standing army, all his allies, and Metal Gear, with no hope of attaining any of his initial objectives, he survives getting a missile to the face (the very same missile that ruined the super weapon on him). Assuming they are going to be hit by an air strike and die anyway, he decides to take out the frustration on Snake. He sets up an elaborate death trap to kill Snake's girlfriend involving a piece of dynamite, then has a fist fight on top of the super weapon with Snake to prove his superiority (even though, as previously stated, he took a missile to the face, said missile was also strong enough to knock out Snake; the one who fired it). After Snake defeats him, he seemingly falls to his death, yet still manages to chase them in a machine gun car fight. Then, after surviving a car crash, he still crawls after Snake, ready for murder. Only then does he finally die from a virus he received upon first coming into contact with Snake, meaning his entire encounter was one last stand even before losing everything else.
Dahau in Valkyria Chronicles III. He refuses to obey the peace treaty, and with what remains of his troops, he activates a Valkyrian superweapon. In fact, in this battle, he can't die, even if you sic your Valkyria at him; you must deactivate the superweapon.
Happens about three times in Fire Emblem Awakening. After most of his forces are either decimated or deserted, Gangrel, the king of Plegia, makes his last stand in a wasteland with only a few troops left that are loyal to him. The second is against Emperor Walhart, where the player's army manages to corner him in his own throne room before finishing him off, after killing two of his generals. The last time is against Validar, whose attempt to corrupt the player ends in failure and he is forced to defend himself the old-fashioned way. All three times, a foreboding tune with Ominous Latin Chanting is playing in the background.
In Resident Evil 5, Albert Wesker has lost practically everything by the end. He's killed off and betrayed all of his allies, his resources are gone, and the heroes have just managed to crash his plane robbing him of his only chance to unleash his bioweapon upon the world. All he has left is a single canister of the bioweapon. Wesker refuses to surrender and exposes himself to the bioweapon (which Word of God confirms would have eventually consumed him). All for one last chance to finally kill his hated Arch-Enemy Chris Redfield.
The ending of Baldur's Gate features this. Unmasked before the public as the mastermind of the entire iron shortage and attempted war with Amn, Sarevok flees into some caves underneath the city with his most loyal subordinates so he can go down fighting all the interest groups (the Iron Throne, the Flaming Fist, the Player Character) now out for his head.
In Winx Club, near Valtor's end, he is humiliated by the Winx, loses most of the spells he stole, is abandoned by the Trix, and is nearly crushed by all the water of Lake Roccaluce. He survives and kidnaps the Specialists in order to lure the Winx to Andros and kill them with his last stolen spell, the Spell of the Elements. He ends up losing that and then loses control of his body to the Ancestral Witches before Bloom finishes him off.
Megatron of Transformers Animated pulls one after the initial test run of his superweapons fails and decides to just give up on conquering Cybertron in favor of destroying Detroit and the Autobots who have opposed him over the course of the series.