Empty Room Until the Trap

Secure Front Entera—IT'S A TAAANNNKK!!

This is when a room looks empty of anything significant, and it's not. There's a well hidden trap that will set off if the hero either tries to leave or sets off another trigger, usually by the standard look-see or an Event Flag.

If the hero is lucky, it will just be a monster to fight. If the hero is unlucky, then Have a Nice Death.

Common in adventure video games and Tabletop Games.

Compare He Was Right There All Along, Empty Room Psych (which this trope often leads to), Suddenly-Harmful Harmless Object, Teleporting Keycard Squad, Drop-In Nemesis (where the trap results in instant death), and Ambushing Enemy.

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Video Game Examples:

Action-Adventure

• ANNO: Mutationem: Once Ann finds out Ryan had previously visited Alan Doyle, she heads to Doyle's lab only to find the area vacated. Upon stepping into a nearby elevator, she's suddenly attacked by the MI Mecha.
• The Legend of Zelda:
  • Happens in The Legend of Zelda: A Link to the Past, the dungeon beneath the Village of Outcasts. The compass tells you that one empty room is actually the Boss Room, but there is no boss...until you bomb its ceiling and lead a certain prisoner into the light...
  • The Legend of Zelda: Ocarina of Time:
    • In the first dungeon, Inside the Deku Tree, you have to look up and find the boss on the ceiling.
    • The Mini-Boss room of the third dungeon, Inside Jabu-Jabu's Belly, has a large platform in the center of the room that is inaccessible to you, but to Princess Ruto when you toss her onto it. You have to do so so she can get the third Spiritual Stone, the Zora's Sapphire, which she had been looking for after Jabu-Jabu swallowed her, and eventually becomes yours so you can open the Door of Time in the Temple of Time after the boss of that particular dungeon has been defeated (though not before she holds you to the promise of marrying her). After Ruto takes the Sapphire, the platform rises up to the top of the room, taking her with it, and when it comes back down, Ruto vanishes and you're left to deal with a Bigocto. Moreover, that platform has spikes on its sides, which spin in the opposite direction Bigocto is running in during the fight, but it eventually becomes a one-way elevator to the corridor up above where Ruto was taken to after you win.
      [Link is about to climb up onto the platform to grab Ruto so he can take her home, but it rises up]
      Ruto: Keeeyaaaah! What is this?! An octopus?!
      [the door Link and Ruto came in through seals shut, and as the platform comes back down, Ruto has vanished and a Bigocto attacks!]
    • In the Forest Temple, the boss room is empty. Realizing this, you try to leave, but a spiked gate rises up preventing you from leaving. This triggers the boss battle.
    • In the Fire Temple, you can actually leave the boss room, provided you have not jumped out onto the battle platform yet.
    • Two examples in the Water Temple. Halfway through the temple, you come into an infinite, foggy wasteland filled with ankle deep water and a small island with a dead tree in the center. There's nothing particularly interesting about the room, and when you reach the other side, you find that the exit door is barred shut, and your reflection is gone. Only then will you find that one of the most fun/confusing fights of the game has been waiting, watching you from that tree. It's interesting to note that if you walk backwards to the door, Dark Link will not appear. He will only appear if you turn the camera around so he can't be seen when he appears. When you turn around again, Dark Link will be standing by the tree, just waiting. Even moreso than that, he only appears if you walk over the island in the center, at which point your reflection disappears from beneath you when you step upon the water again. Later, when you enter the Boss chamber, Navi warns you that the water in it is not ordinary water, and when you jump on one of the four platforms, Morpha appears, beginning the battle.
  • The Legend of Zelda: Twilight Princess:
    • One room in the Lakebed Temple appears to be empty at first and Midna advises you to look around. Then you realize that small tadpole-like enemies are dropping down from the ceiling, and you look up to see the dungeon's mini-boss, a giant toad, who drops down to fight you.
    • The miniboss room in Arbiter's Grounds has a large sword embedded in the center of the room, but when you cut one of the ropes holding it onto the floor, it burns away the other ropes and an apparition appears wielding it, which can be seen in wolf form until you make it partially solid enough to attack it as a human.
    • The miniboss in the Snowpeak Ruins is in what looks like a simple hallway with two suits of armor on display. Then when you get to the other end of the hallway both doors suddenly lock and the suit of armor immediately behind you is smashed by the other one, which comes to life wielding a ball and chain, which eventually becomes yours after you've defeated it.
  • In The Legend of Zelda: Skyward Sword, the Sandship requires visiting three Mini Dungeons in Lanayru Sand Sea to find the next main one. The final room of the second initially looks like an empty room with some sand, but after some dusting Moldarach (the final boss of the Lanayru Mining Facility) inexplicably shows up for a rematch, now as a miniboss.
• In Ratchet & Clank Future: A Crack in Time, this is lampshaded. After going through two of these in the Valkyrie Citadel where enemies suddenly drop in, Ratchet is not surprised by the third.
• Star Fox Adventures: When Fox enters the empty chamber in Cape Claw, he audibly starts choking, revealing he's in a gas chamber.

Adventure Games

• Monkey Island 2: LeChuck's Revenge has the seemingly empty guest room in the Woodtick Hotel. If you wait in here a while without going behind the dressing curtain Largo LaGrande will come in here and shout at you for coming in his room, and then kick you out. And then later on, you set a trap for him, in the very same room! Even later, you have to come in there with the Voodoo Doll and shock him. After this the room is really empty. These scenes are echoed in the last act of the game. You are in an underground building where you have to search several empty rooms to gather various items to build a Voodoo Doll of LeChuck. However, at any given point, LeChuck can enter the room and electrocute you. You therefore have to build the Voodoo Doll and be able to immediately use it on him when he walks in.
• Inverted in Robot Odyssey which forces you to do a puzzle to get a token each time you need to ride the subway. Because of this, players are hesitant to get off at Jack-in-the-bot station because there are no doors in the room. They appear and open only when you get off the subway.

First-Person Shooter

• BioShock had a few of these. Examine a certain item placed in the corner of a room, and when you turn around — surprise! There's a splicer right behind you that wasn't there a second ago! "Hello, beautiful!"
• 'Doom³'': A frequent case, to the point it doesn't shock or surprise the player after a while. They just knew as soon as they entered the empty room and touched the item they'd immediately have to turn around and blast all the monsters that teleported into the room.
• Many side rooms in the Medal of Honor series only serve to trigger ambushes.
  • In Medal of Honor: Vanguard as soon as the player walks into the empty lounge in the Chateau after clearing it out, a Panzer 4 will blow a hole in the wall and several other tanks supported by infantry will spawn around the Chataeu.
  • Another variant of this is used later on, where there is a large, seemingly empty room in a factory filled with snipers, however the snipers won't spawn until the player is close enough, preventing the player from clearing out the room from a distance.
• Boss rooms in Quake II and Quake IV tend to be empty of enemies until the boss suddenly teleports in. This is usually triggered by the completion of an objective, such as shutting down the security grid in II, or the Tetranode in IV.
• All over the damn place in Serious Sam games. You'll frequently encounter places that are empty except for a powerup or two. Go far enough into the area, or pick up the powerups, and mooks start teleporting in en masse.

Puzzle Games

• Trapped 5 has the first two boss rooms marked only by a preceding hallway with a question mark on the floor that says "Beware" if you examine it. You enter the room and the door locks behind you. Once you go up to the other door, then the boss appears.

Role-Playing Games

• In Fallout 4, the Very Definitely Final Dungeon of the Automatron DLC has a long hallway lined with apparently empty jail cells. However, if you hit the circuit breaker on the wall, which happens to be inconveniently placed next to an elevator switch, a dozen high-level Feral Ghouls emerge from the cells.
• Final Fantasy:
  • Final Fantasy II has many empty rooms with very high encounter rates. It drops you off in the middle, and you'll probably have to fight a battle or two on your way out.
  • Final Fantasy IV
    • The infamous "closing wall" room (just before the throne room) in the Baron Castle, which has no significance until you try to walk back through it after you beat Cagnazzo, and requires the death of two of your party members in order to proceed.
    • The bridge in the Sealed Cavern. You walk across a bridge and get the Dark Crystal of Earth, then walk back onto the bridge, where you're confronted by the Demon Wall.
• Parodied in Kingdom of Loathing's Daily Dungeon. The protagonist recognizes the trap rooms instantly (and with some weariness), and can either trigger them (which does enormous damage but removes the obstacle)) or set them off at a distance with an item.
• Mass Effect:
  • The first encounter with the rachni on Noveria in Mass Effect includes at least one rachni soldier popping out of a vent as Shepard leaves the room.
  • Mass Effect 2 has both the Collector ship from the standard game and the geth ship from the Overlord DLC, which have upgrades, money and the like dotted around, but either the enemies are inert, or they're not visible at all. In both cases, you reach a well-defined midpoint, and then everything goes to hell in moments.
• Pokémon:
  • The "Monster Houses" in the Pokémon Mystery Dungeon series, which appear empty until 30 or so enemies drop from the sky the moment you set foot in them.
    • Unless you scan for items, since such trap rooms tend to have abundance of loot.
    • Also at the beginning of secret episode 4 in Explorers of Sky (Here Comes Team Charm), a Graveler walks into a room with a treasure chest and statues of Lopunny, Gardevoir and Medicham, long story short the statues come to life and take the treasure for themselves, (info can be found here).
    • Such "Monster Houses" are common in Pokemon Mystery Dungeon's genre, but they are usually filled beforehand.
  • In Pokémon Diamond and Pearl, there are a couple of occasions like this. The first is the ghosts in the Old Chateau which will appear out of nowhere even if the rooms look empty. The second is a small room in Stark Mountain, where the room seems empty until you leave and go back in, at which point Heatran has appeared from nowhere.
• In Shin Megami Tensei IV, one of the shelters in Kasumigaseki has a room that can only be accessed by having at least 100 Luck. Open the room and you find absolutely nothing...unless the RNG decides to fall on the 1/256 chance of Red Rider appearing in that room, though you will be given a chance to leave if you aren't up to the task.
  Burroughs: "I'm detecting a very dangerous demon nearby. You should consider getting out of here."
• Tales of Symphonia uses this to remove characters from your party just before the (apparent) endgame; there are six rooms that the heroes pass through, and in each one is a trap of some sort that requires one party member to stay behind to hold open a door, hold off enemies, etc.
• Under Hero: At the end of the graveyard in World 2, Masked Kid goes through an area with no enemies or other dangers and retrieve one of the relics needed from the mausoleum. On their way back, however, they encounter the Grey Kid.

Shoot 'em Up

• Abuse has a nasty habit of putting players in that appear empty, but as soon as they flip a switch or advance further in the area and—WHAM! A horde of mutants show up and starts ganging up on them.

Survival Horror

• Dino Crisis: In most rooms that hold a significant item, as soon it is taken, a dino will burst in from somewhere.
• Left 4 Dead has these in the form of crescendo events. In most levels, there will be a room that will have a few zombies, but won't spawn any more into the map until the survivors press a button or something that alerts a horde to their location.
• Resident Evil has the room with Plant 42, the attic, the inaccessible room upstairs in the mansion, that when you get the key and go in its empty until you examine the piano, then Giant Mutant Snake. Its first strike at the player breaks a hole in the floor that gives you access to the basement, which is only accessible after the boss fight.
  • There's also the infamous tiny, nondescript room you pass through before finding a shotgun innocently hung on the wall. Unless you like Jill Sandwiches, you'd better have a replacement for that shotgun or Barry to save your butt.
• The bathroom in Silent Hill 3.
  • Later on, the "bloody mirror room" in the alternate hospital.
  • Take the dagger out of the fridge in Silent Hill without first locking the door with the Ring of Contract, and an unknown monster comes out of the fridge and eats you.

Examples From Other Media:

Anime & Manga

• JoJo's Bizarre Adventure:
  • Diamond is Unbreakable: While investigating Yoshikage Kira's house, Josuke and Jotaro are attacked by Yoshihiro's Atom Heart Father when he traps them in a photograph room.
  • Steel Ball Run: Johnny, Gyro, and Hot Pants are in an empty building filled with trash until each of them get haunted by figures from their past once Axl Ro's brings out his Civil War.
  • JoJolion: After spending some time with Tsurugi in his secret room, Yasuho takes a moment to rest by herself until it's shown Yotsuya Yagiyama managed to slip in and tries to kill her.

Film — Live-Action

• Virtually every room in Cube. Two characters are killed by a Razor Floss wire trap, and one is killed by giant speakers that pulverize his body with sound waves. Fridge Logic dictates that they should have been able to see the Noodle Implements that should've killed them, but they don't. The characters soon catch on to this, and start throwing boots and other objects into empty rooms before going in.

Literature

• In The Expanse the Tecoma system is unnaturally empty. There's a neutron star on the very edge of collapse into a black hole and nothing with mass down to the subatomic level. After the Laconians drop an antimatter bomb on the Precursor Killers there's a sudden, massive uptick in quantum effects that starts causing hydrogen to be generated, tipping the neutron star's mass just over the limit creating a gamma ray burst that proceeds to destroy the system's gate, the gate opposite that gate in the Slow Zone, and everything in between.
• This backfires in The Princess Bride. When Inigo and Fezzik rescue Westley from the Zoo of Death, they traverse a floor that is dark and completely empty. The two of them freak out because Nothing Is Scarier, and rush to the door. The intention behind the room is to make people panic and get bitten by the spider beneath the doorknob. But Inigo and Fezzik are so terrified that they bypass the intended trap by knocking down the door and crushing the spider.

Tabletop Games

• Dungeons & Dragons has a monster that pretends to be a ceiling, and a monster that pretends to be the floor, monsters that cover the walls and almost invisible jelly monsters in the size of a usual Empty Room. Combine them all to create the infamous Room of Death, which appears empty until all of it tries to eat you.
  • And they actually did it in module X2 Castle Amber.
  • Put the monster that looks like a treasure chest in the middle and the monster that looks like a door on the far wall, and you've got the Room of Vile Death. Put a pool of the monster that looks like water in the corner, and you get stuck with the whole pizza bill for the night.
  • And of course there's not a DM alive who has never used the Paranoia Fuel aspects of this trope to get their players worked up over a genuinely empty room. It's fun to watch them poke every square inch of a 10x10 room with a stick, swing their swords in a panic at casually mentioned details like some moss in the corner, and maybe even waste spells trying to divine the room's purpose or buff themselves up for a fight that never happens.

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