Villain Override

It's the next-to-final battle, and the heroes are moving in on the fortress. The Big Bad dispatches his Quirky Miniboss Squad, but while they pose a challenge for a while, they too fall. He is obviously miffed, but it's not like he can go out there himself...

The next thing that the fallen minions see is their boss' face looming above them. He informs them that they have failed, and they panic and retreat -- and suddenly stand up with Mind Control Eyes. Healed to full and twice as strong, they rush at the heroes again, but something's wrong. The Big Bad is possessing them to finish the job.

A favored trick of The Man Behind the Man, to show that he really is the biggest threat despite hiding in the back.

A form of Sequential Boss. Contrast I Know You Are in There Somewhere Fight, Heroic Willpower, and Brainwashed and Crazy, which use heroes as the controlled. If the miniboss(es) survive, expect a quick Mook Face Turn, or that they were Good All Along.

Compare Berserk Button and Brainwashed. This is basically Mass Hypnosis or Face Monster Turn done to one's allies instead of the enemy.

Anime & Manga

 * In the Battle-City arc of Yu-Gi-Oh, every time one of Marik's minions (the Rare Hunters) was defeated, the symbol of the millennium items (the Eye of Wadjet) appears on their forehead, and they start talking in a notably different voice as Marik is now controlling them through his Millennium Rod, having sent their minds to the Shadow Realm. Almost always preceded by "Master! I'm sorry! Please don't -- *evil cackle commences as Marik takes over*"
 * The finale of the Pure arc of Mermaid Melody Pichi Pichi Pitch. It looks like have finally been reached by The Power of Friendship,, fears that his plans will go to waste, and overrides.
 * In Magical Girl Lyrical Nanoha Strikers, Quattro does this to Lutecia when it seemed like the words of Caro and Erio were finally getting through to her. This causes her to Summon Magic a large amount of giant insects against the two, including one that's approximately the size of Godzilla.
 * Happens to the sleeper agent Anew Returner in Gundam 00 when she decides to forego her mission and stay with her boyfriend,.
 * In the final battle with Sensui in Yu Yu Hakusho, this happens to His demonic ancestor possesses him, boosting his power ridiculously high and easily dispatching his enemy. He doesn't like being made into a puppet like that, though.
 * In the final episode of Sailor Moon's first season, The Man Behind the Man Metallia merges with Big Bad Queen Beryl.
 * The anime only Amagai arc from Bleach features a series of weapons used by the villains. Kumoi's assassins and elite soldiers are given named Bakoto with unique abilities that grow more powerful depending on the user. The mooks are given unnamed Bakoto that only do this.

Film

 * Happens during the final battle at the end of Tron. The Master Control Program transfers his functions to his damaged minion, Sark, making him grow many times his size.
 * And then Kingdom Hearts II reenacts this in the world based upon the movie.
 * Happens to the dead Septimus in Stardust.
 * The agents in The Matrix can override anyone that is plugged into the system.
 * Real Steel has both a heroic and a villainous example. During the final round of the climatic fight, both Charlie and Tak assume direct control of their respective robots.

Literature

 * In Brisingr, Galbatorix does this to, turning the tide in the battle against.

Live Action TV

 * Super Sentai has done this a few times recently:
 * The Go Go Five finale has the Big Bad do this to her Dragons for a final battle, and is killed when they are. (Power Rangers fans, you know this episode as Rise of the Super Demons. In the sentai version, "Olympius" and "Diabolico" both spoke with the voice of "Queen Bansheera" after that lightning spell thingy. If you're wondering about their bizarre death scene and the Rangers being way too happy for having just had to kill Diabolico... it's 'cause this is what was happening in the original scene.)
 * In Abaranger, Desumozorlya is a disembodied consciousness who communicates by controlling the body of minion Rije/Rijewel. Near the end, he controls Rijewel almost full-time, using her to do battle.
 * Speaking of Power Rangers, there's always Ivan Ooze taking over Hornitor in the final battle of the movie, although in that case the possess-e wasn't exactly sentient to begin with. After the Ninjazords destroy Scorpitron, one of Ooze's two mechs, he merges with the remaining one.

Tabletop RPG

 * In Exalted, every Primordial/Yozi is capable of possessing its souls and (in the case of their fetich) harnessing their own Charms through them.

Video Games
""She breaks the seal and becomes a giant. What monster is this child?!""
 * In the first Galaxy Angel game, the mercenary Hell Hounds, despite being evil counterparts of the Moon Angels, fall pretty easily in their last fight. Noah appears on the monitors in their pseudo-Angel Wings, takes control of the ships, and shoots out glowing thread into the backs of their heads to control their minds. The next battle has them significantly stronger.
 * In the manga, this is partially subverted, in that the effect makes them weaker against the Emblem Frames' Eleventh-Hour Superpower upgrades, which would not have likely had any effect had they NOT been under Noah's control.
 * Several times during the original Xenogears game. Just as the party was finishing off a particular boss, Grahf would appear, give a short speech about the nature of power or whatnot, and brainwash and/or transform said miniboss into a more powerful form.
 * "Doth thou desire the power?"
 * Virgil uses this to Kick the Dog in Xenosaga, forcing the already mortally wounded Realians to drag themselves into a suicide attack. Somewhat subverted by the fact that they were okay with it.
 * In Silhouette Mirage, after winning the final battle with Zohar, Har dramatically reveals that he's a Guardian Angel and disables his free will, allowing him to access his true power and transform into the gigantic, polygonal Cypher Zohar.
 * Subverted touchingly in Super Robot Wars R where the Big Bad is fatally wounded by the heroes, and her Replacement Goldfish sacrifice their souls to heal her... but their bodies keep going, still determined to carry out their last wish... Even more touchingly, the Big Bad asks each of them what they desired, promising to fulfill it when she resurrected them.
 * Occurs with a slight twist in Dark Cloud 2. Emperor Griffon takes over Gaspard after Gaspard is defeated.
 * In Hollow Bastion in the first Kingdom Hearts, after near the beginning,, showing up later as the penultimate fight for that world. He proceeds to give Maleficent a Villain Override as well, forcibly turning her into a dragon for the heroes to fight and kill.
 * Arguably what happens to Manah in Drakengard towards its first ending. Not obvious in that ending, but later endings seem to suggest that a Villain Override is happening here.


 * After you beat the Big Bad of Cave Story, he returns and posesses The Dragon (who'd been trying to convince the hero to leave and not to destroy the island's core), the Distressed Damsel, and the "core" of the island, for a three-on-one fight.
 * Subverted during Statesman's Task Force in City of Heroes. Turns out that Lord Recluse's lieutenants were buying time for his A God Am I powerup machinery to come online. After they fall, he comes out to deal with your team of superheroes himself.
 * In Mass Effect, after you defeat This actually proves to be a mistake;.
 * Mass Effect 2 has Harbinger, the Collector General, who commonly takes over a Collector drone in the middle of -- 
 * And because he can do this to any active drone, he can pull this trope off more than once in any given -- 
 * In fact, he does this so often as to reach Goddamned Bats stat -- 
 * Don't forget the parts where he'll take over a Collector that you're about to finish -- 
 * Inverted in the final sequence. As the
 * In Fire Emblem 7, (the first released outside Japan) Nergal summons morphs in the form of all the hardest enemies fought previously, but with the best weapons in the game and much higher stats. It's implied that they're actually the originals whenever you kill them.
 * One of Falkner's favorite tricks in Vanguard Bandits is to give your apparent allies a dose of Brainwashed and Crazy once you're done with his Mooks. In the bad ending of the main story branch,
 * in Persona 4 first reveals itself when Also something of a Giant Space Flea From Nowhere.
 * Happens in Mega Man and Bass.
 * In Mega Man Battle Network too, with.
 * The World Ends With You has Uzuki and Kariya fighting the protagonist over three days. First Uzuki alone, then Kariya alone and both in the same day, and then both of them, somehow upgraded by The Dragon's master plan.
 * Super Paper Mario has you fight recurring boss O'Chunks several times. In your penultimate fight with him, fellow Quirky Miniboss Squad member Dimentio plants a leaf on his head that causes Mind Control and strengthens him. Subverted in that you fight him once more later, when he's holding nothing back, and he's even stronger.
 * One of the purer examples is in Dungeon Keeper (especially the first game). Using your possession spell to directly control a minion, that minion is faster, stronger, tougher, can ignore bodily needs almost indefinitely, can deliberately dodge attacks, and can fight intelligently for a change. You are the Villain Override.
 * In the second game, certain creatures also got unique abilities while you possessed them (such as the rogue's camouflage, or the giant's dwarf tossing) and enabled you to disable traps and unlock doors. This last one turned out to be such a Game Breaker that it was disabled in a later patch.
 * The second Overlord game requires you to do this to complete a few areas. Most of these sequences are simply a matter of your minions entering an area that is to small for you in order to remove and obstruction and let you in, but there are a couple of longer sequences.
 * In the Shadowfall War in Adventure Quest Worlds, the evil lich Noxus does this to, which counts as this instead of Mass Hypnosis due to the fact that . The only to escape Noxus' control?.

Western Animation

 * In Teen Titans, Slade takes control of Terra via the suit she's wearing after her rematch with the Titans went poorly. It didn't work out very well for him.