Monster Closet

Say you're a Space Marine in a completely normal space facility. You pass by an innocuous piece of wall, and then suddenly - SHOOM the wall opens behind you to reveal a 2-foot by 2-foot square completely empty except for a demonic space monster trying to burn the back of your head off.

Primarily a First-Person Shooter trope. It's mainly present in older first-person shooters as it's becoming largely discredited, due to better storytelling techniques or replacing it by offscreen or onscreen spawning.

One must question a few aspects of this situation:
 * 1) Why is there a random closet in the wall that isn't being used?
 * 2) Why is it hidden? (Although being hidden does sort of explain why they weren't used)
 * 3) Why do so many of them have monsters in them? How did they get in there in the first place?
 * 4) Why does it automatically open as the Player Character passes by? If the monster could open it from the inside, why did it stay in there?

A form of Malevolent Architecture.

Compare Teleporting Keycard Squad and Mook Maker.


 * Doom did it a lot. Often times rooms would be just a pedestal with an item on them, but taking the item opens up all the walls to reveal nasties.
 * They did it with Doom 3, where it stretched believability to the breaking point. "They're breaking through the walls!"(radio transmission)
 * Half-Life explains it by way of the monsters getting into unused drywalled-off corridors due to random teleporting.
 * Freemans Mind points out that not only is this the reason the facility is falling apart, but that an alien could teleport into a person. At any time.
 * Portal explains where the turrets-in-the-walls come from by showing you a whole distribution system for them criss-crossing the entire facility.
 * Serious Sam does it occasionally.
 * While the closets in Left 4 Dead are not hidden, several contain absolutely nothing except respawned survivors. However, sometimes a Horde may spawn in it.
 * Also, some walls are fragile and allow zombies to burst through them.
 * Since the AI Director chooses which closets are used, exploring players will find empty dead ends that could have been monster closets.
 * Hordes of 30 zombies spawning out of a closet is pretty much one of the main game mechanics.
 * At least in the spirit of this trope, tho, as you play Left 4 Dead or Left 4 Dead 2, you will encounter plenty of zombie configurations that will make you stop and ask, "How the hell did this happen? How did these guys get here? Why did they stay?"
 * It can also lead to unintentional hilarity when a witch spawns in a closet. Open door, toss in molotov, close door, wait for the screaming to stop. Repeat as needed.
 * It's been almost entirely replaced by "Ah, they're coming out of the air vents!" in video games. For instance, Mass Effect 1 does this with some of the . Though the exact same problems apply to those as do to the monster closets.
 * Resident Evil: Dogs and zombies coming through windows? Check. A zombie bursting out of a literal closet? Check. Licker crashing through the one-way mirror? Check.
 * Oven Man from Resident Evil 4. Leon will even lampshade this by wondering what he was doing in there.
 * The Quake series does it sometimes in the first 2 installments.
 * The first video game adaptation of the classic board game Space Hulk sometimes features Genestealers popping out of the walls - usually right behind one of your Marines. No sooner do you hear "Ambush!" then you hear the death scream of the unfortunate Marine.
 * Happens in Ayleid Ruins in Oblivion, though this is at least handwaved by the fact that Ayleid ruins are notorious for being booby-trapped.
 * Many examples in Duke Nukem 3D, many of which could be avoided by using the jetpack to quickly fly over the Event Flag.
 * In La-Mulana, removing a certain section of wall in the Temple of Moonlight releases a whole bunch of Goddamned Bats. Amazingly enough, this is not a trap.
 * Skewered and fricassed in Zero Punctuation's Review of Dead Space 2, a modern adherent to the original version of the trope. The narrator notes that monsters pop out of identical air vents so often there's no surprise when they do, but that the air vent doesn't go anywhere, suggesting the poor beastie had to pry off the cover, put the cover back on once it was inside, and just take a nap. Since Dead Space is a Survival Horror game, knowing where the enemies are all but guaranteed to jump out from certainly removes a ton of suspense.
 * The first Unreal, generally averted this trope, placing enemies in sensible positions, still plays it straight once near the start. Up to that moment you've only encountered Brutes (slow and easy to kill, if quick to shoot), tentacles (plants that shoot nearly harmless spikes) and birds (quick but easy to dodge and kill), wiping out the whole of them. The task at hand is to deactivate a generator powering a forcefield. Upon coming back from this task, the long, narrow corridor you've already walked through before starts getting dark, as lights switch off.
 * Does Monsters Inc. count as a non-videogame variation? Technically, the closets aren't hidden, but it's impossible to tell from the outside when one of them's gonna open and reveal a monster.
 * These are called "vaults" in the Roguelike genre, though typically they don't open up on their own; either they have (often hidden) entrances, or you have to dig your way in.