The hero/villain has defeated their final target, they stand triumphant, only for an entire army to appear out of thin air, apparently they were all hiding, waiting for a signal of some kind.
This army could be as few as four or as many as thousands, but they must appear out of nowhere and surround the character.
The method of hiding isn't important as long as the area appears empty on initial inspection and leaves the character wondering where the hell they came from.
Note: To clear up any possible confusion. For something to be an example of this trope the army in question needs to be physically present, but not visible. This means teleporting in armies don't count. This trope can overlap with You and What Army? and The Cavalry, indeed an example might be present on all three trope pages.
- In one Batman comic, Batman and Ras al-Ghul are talking, with a bunch of his assassins revealing themselves around the two (they were buried in the sand).
- Mulan: As Mulan's unit is attacked by snipers in a mountain pass, they fire cannons at them, which seems to hold them off. But then, as the smoke clears, Shan Yu appears at the top of a ridge. And just behind them, about a thousand Huns on horseback...
- GoldenEye. Near the end of the film a field full of marines and a couple of helicopter appear at the shout of "Yo! Marines!" (Youtube clip)
- Predator 2. Several predators de-cloak just after the hero has finished killing one. Apparently, they were watching, and approve.
- In The Return of the King Aragorn pulls this when he arrives at the battle of Minis Tirith. What appears to be just one man charging at the enemy is suddenly one man followed by an Army of ghosts.
- Villain-to-villain variant: Earlier, in The Two Towers, as Grima Wormtongue and Saruman walk-and-talk around Saruman's Mage Tower, Grima points out that the fortress they want to besiege is filled with basically all of the Rohirrim, and that capturing it would take thousands of troops. Saruman corrects him to "tens of thousands". Grima complains "But my lord, there is no such force" before Saruman leads him to a balcony above tens of thousands of Uruk-Hai. (Grima apparently didn't hear any of the super-soldier orcs shouting until he could actually see them.)
- In Serenity, this tactic is used to get past the Operative's fleet surrounding Mr. Universe's planet. The planet is surrounded by an ion storm which can mask a ship's signal — The Operative sees the tiny Serenity and assumes he has won already, before an enormous Reaver fleet that had been chasing Serenity emerges from the ion cloud behind it. The Alliance wins the resulting battle, but Serenity gets through the blockade in the chaos.
- In Keep Your Powder Dry (1945), some female soldiers have a picnic and go swimming in some sort of lake. A male officer comes up to them, tells them there's a 'problem', and marches his dozens of camouflaged men away.
- In Harry Potter and the Deathly Hallows, Voldemort appears to have the battle won, when The Cavalry — Professor Slughorn, the centaurs, the giants, supposedly (says non-canonical Word of God) a bunch of Slytherins — explode out of the Forbidden Forest and attack the Death Eaters. Voldemort and company are routed.
- Sharpe: Sharpe's Waterloo has this twice.
- Sharpe tells Upper-Class Twit Prince of Orange that the battlefield is not empty, as the Prince keeps saying, because there are heavy cavalry hidden in a patch of dead ground behind a rise. The Prince gets a nasty shock when the cavalry turns up.
- Napoleon is surprised by a sudden appearance of reserves for Wellington's army, because Wellington had some of his troops (also Real Life example) lie on the ground just behind the crest of a hill so they could not be seen until he gave the order to stand up.
- In Doctor Who, "A Good Man Goes to War", the Doctor tries to create a Let's You and Him Fight scenario between two armies united by their desire to kill him. The leader avoids this by having his men unload their weapons... at which point the Doctor's backup decloaks and it turns out they are surrounded by an army of the Doctor's allies.
- Star Trek: The Next Generation: In "The Defector", Picard is ordered to take the Enterprise to investigate a suspected Romulan base located in the Neutral Zone. As it happens, the leaked intel regarding the Romulan base was a Batman Gambit by the Romulans to lure the Federation into violating the Neutral Zone and giving the Romulans casus beli to destroy Enterprise and declare war on the Federation. As soon as Admiral Tomalak finishes boasting to Picard, a squadron of Klingon Birds of Prey uncloak around the Romulan ships, ready to destroy them as soon as they open fire. Tomalak withdraws without a fight, and war is avoided.
- Call of Duty
- There's a moment in Call of Duty 4: Modern Warfare where the player starts out looking at what appears to be empty grassland, even after a replay not really knowing where their ally is until part of the ground gets up and starts moving.
- Call of Duty: Modern Warfare 3 does a non-foliage variant during the stealth mission in Prague, where Price sneaks up on and takes out a sniper on a rooftop just as the player is sighting in on him, then when told about how lopsided the odds are, reassures you that he's "brought friends" - cue as many rebels as could possibly fit on that rooftop revealing themselves and opening fire on the opposing army.
- The climactic battle in the eleventh season of Red vs. Blue begins this way, with Locus showing up seemingly alone and the other Feds uncloaking soon after.
- Girl Genius shows an example of this being used as a legitimate military tactic. During the siege on Mechanicsburg, the Baron's army appears to be in complete disarray for a portion of the proceedings, until the Baron decides it is time to make his move, at which point the "misdirection and phantasmagoric" units, which had in fact been creating the appearance of disarray deliberately, fall back to reveal an incredibly large, regimented and well-organised army that had been obscured by the maelstrom.
- Storm Hawks pulls this in "Terra Deep" as a Shout-Out to above-mentioned scene in Serenity. After spending the episode first being chased into the cloudy Terra Deep by a fleet of Cyclonian ships that block the way out then being chased and caught by the Murk Raiders led by Captain Scabulous inside, the Storm Hawks finally defeat the pirate boarding party and take off. Scabulous, however, refuses to give up the chase and with his two newly arrived ships keeps after them. Outnumbered, outgunned and being rapidly gained on, Aerrow orders Stork to take the ship back out the way they came, and the Cyclonian commander is initially triumphant just like the Operative before the giant Murk Raider ships emerge from the thick clouds behind the Condor. Scabulous decides the Cyclonian warships are much better pickings than the (relatively) tiny Condor and orders his fleet to attack them instead, the commander is forced to abandon chasing the Storm Hawks to fight the Raiders, and the Storm Hawks escape in the ensuing chaos.
- Just prior to Operation Bagration, in June 1944, Soviet forces manage to completely surprise German Army Group center in Belarus by pulling off this trick, mainly by only moving their troops and vehicles forward at night, and making it seem to German reconnaissance planes that they were moving out of Belarus and into Ukraine. German High command, falling for this trick, move their best troops out of the area and into Ukraine, leaving the front lightly defended. By the time the offensive actually takes place on the 22nd, the Germans are completely dumbfounded when Soviet tanks and infantry emerge from the swamps.
- During the Korean War the Chinese managed to move several hundred thousand troops to the border of Korea in complete secrecy by moving only at night and constructing camouflaged camps to hide from air patrols, soldiers were ordered to stay completely still if an aircraft passed by upon pain of death. Their offensive was so fast and unexpected that many UN commanders didn't believe the Chinese were involved at all in the beginning stages.