Border Patrol

Samos said not to swim to the island.

"It is pitch black. You are likely to be eaten by a Grue."

— Zork

The Border Patrol is a monster or other hazard introduced specifically to provide an in-universe reason for why the player isn't allowed to wander too far off the game map without resorting to an immersion-breaking Invisible Wall^note There probably is an invisible wall, it's just too far out to reach before the Border Patrol stops you or Insurmountable Waist-Height Fence. This often takes the form of an Invincible Minor Minion that you have to run away from or an obvious environmental hazard that you can't survive. Sometimes this will be an Instakill Mook. Sometimes the Border Patrol monster can actually be killed, though it's just as likely to respawn if the game designers anticipated your violent yearning to be free. When done well, the player is deterred by the dangerous thing and returns to the field of play. When done badly, the player character is unavoidably killed by the whatever, with no explanation as to what they did wrong or why they were just killed.

Since it's fairly common to have game maps be surrounded by water, and border patrols generally have to be able to pop into existence anywhere at a moment's notice, big aquatic predators that emerge from the deep to gobble you whole are a very common way to do this — sharks in particular are very common, as are more generic Sea Monsters. Another common form of this trope is a barrage of missiles or gunfire that keeps up until you're dead or back in the play area.

Can be Nightmare Fuel if unexpected (or even when it is expected). If it returns you to a particular location when it catches you, it's also a Mook Bouncer.

Naturally, savvy (and glitch-happy) gamers just love figuring out how to get around these.

See also Beef Gate and Broken Bridge where you are expected to be able to bypass the monster or obstacle, but not right away. Compare Boundareefs, where the monster is replaced by an impenetrable line of rocks. More player-friendly examples of border-enforcing in which NPCs will tell you to come back after which you're forced to return fall under But Thou Must! Related to Drop-In Nemesis. Not to be confused with members of the US Customs and Border Protection Agency, which fall more under Checkpoint Charlie.

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Examples:

Action-Adventure

• Alone in the Dark:
  • In the first game, the thing outside the front door, and the Chtonian Worm that blocks the secret passage from the basement (which you need to unlock anyway to get back in later).
  • In the second game, you'll be shot dead via drive-by if you try to leave the mansion grounds.
• Assassin's Creed has the Animus acting as the Border Patrol. In-game, you are reliving the memories of your ancestors through a virtual machine, and are thus logically limited to the areas that they actually traversed and which the computers can simulate.
  "Area not available in current memory. Desynchronization imminent."
• Beyond Good & Evil: There are occasional barriers than can be bypassed, Zelda-style, with various upgrades to the hovercraft. However, attempting to cross the farthest-out barriers results in a warning, followed by non-damaging shots that blast you back within the borders of the area. It is, however, possible to bypass them with glitches - and drive more than half an hour to make the screen turn black and make you reappear on the other side of the map.
• Fe has a river-dwelling fish that devours Fe if they go out of bounds via water, usually to prevent players from reaching areas that the plot hasn't directed them to yet.
• Infamous: Cole MacGrath has a weakness to water; any amount greater than a puddle will cause him to electrocute himself. Since Empire City is an island and New Marais is in the middle of a swamp, leaving either city becomes impossible.
• The Legend of Zelda:
  • The Legend of Zelda: The Wind Waker has a large, seemingly limitless ocean overworld, but it does have its limits. Ordinarily, Link can't sail past set boundaries outside the map (the King of Red Lions, Link's talking boat, stops, tells him it's too dangerous to go any further, and turns around automatically) but if Link swims instead, he can pass the original boundary until he drowns and respawns at the nearest land. However, with cheats, one can have Link swim even farther out... until Link drowns anyway. Yes, even with cheats that let Link swim forever, he still drowns at a set distance that the player cannot reach without cheating. Granted, there's nothing at that distance away from the map, but there's still an insurmountable obstacle that one cannot even reach in normal play.
  • The Legend of Zelda: Breath of the Wild has winds that push Link back if he tries to go too far out to the ocean or desert, with a constant sandstorm being added in the latter for extra measure. If the player just rushes past these or tries to go past another boundary (such as the mountains by the edge of the map or crossing the giant canyon to the north), the game will just throw an Invisible Wall and a "you can't go any farther" message.
    • Also in BotW, there are the infamous Void Boxes around the Great Plateau that only disappear when you get the Paraglider. Making contact with either causes Link to "void out" as if he fell down a Bottomless Pit, and respawn him either definitively on the Great Plateau, or the last bit of solid land he stood on. Do it just right, however, and he'll loop between respawning and voiding out until Link finally dies.
• Ōkami has the water dragon. It is actually possible to bypass it using the lily pad brush power, but it's very difficult to do. As the story progresses, the dragon becomes less of a problem with the help of Orca, who is faster than it (and immune to its attacks anyway). Later on the dragon is killed, allowing the waters to be traversed safely.
• Ratchet & Clank uses hungry fish in areas with water you're not supposed to be in.
• Sphinx and the Cursed Mummy features the water-surrounded city of Abydos. Since Sphinx can swim, however, the water surrounding it is filled with electric eels that make the water an insta-kill. Oddly, the Hub Level is also water-surrounded, but doesn't do anything about it — you just hit an Invisible Wall.
• Tomb Raider III: The Aldwych level has several subway tubes you go through to progress and backtrack. Going beyond the intended point will have a subway car suddenly appear in front of you and hit you for a One-Hit Kill. There's no way to avoid them or getting around them.

Adventure

• Gothic II has a friendly sea monster come a-calling when the hero tries to swim too far from the island chain he starts on. And if the player survives this somehow and keeps going forward, the game will also throw piranhas at them for good measure.
• The Journeyman Project: If you walk up the pitch-black maintenance transport tunnel, the tram runs you over, and the Have a Nice Death screen says "Well, at least you weren't eaten by a grue!" Also, if you enter the main Mars Colony or go out of bounds at the World Science Center, you will be "Caught by Security".
• King's Quest V: Absence Makes the Heart Go Yonder!: King Graham can find himself sailing straight into the maw of a sea monster if he goes too far out at sea.
• In Space Quest III: The Pirates of Pestulon, on the planet Phleebhut, if you wander too far south you get eaten by a giant snake while wandering too far north will have you struck by lightning.

Fighting Games

• Super Smash Bros.: A large shark swims around in the water on the edges of the Tortimer Island stage, and will attack any players that approach the edges.

First-Person Shooters

• Battlefield has a commanding officer instruct you to return to the battle or you will be shot for being a deserter; after ten seconds, you'll take fast constant damage until you either die or return to battle. Especially diabolical if you do this in a transport aircraft or aircraft carrier and doom all of your teammates too.
  • This is actually used as a griefing tactic in Battlefield 2, mostly to allow the pilot of an attack helicopter to kill the gunner only, by pointing just the gunner (who sits in front) on the edge of the border, waiting for them to die then picking up the friend you wanted to be the gunner.
  • Battlefield: Bad Company: When crossing the map border, you receive a radio message that enemy artillery is active in this area. Although it makes less sense after the squad goes AWOL.
• Call of Duty:
  • Commissars will shoot you dead in the Soviet campaign if you run from the battle.
  • Several levels in the series are lined with minefields around the combat zones.
  • In the Call of Duty 4: Modern Warfare level "All Ghillied Up", set in Chernobyl, wandering off the path will result in getting hit by a "lethal pocket of radiation".
  • Call of Duty: Modern Warfare 2: In "No Russian", a blockade of infinitely respawning police officers will gun you down if you venture too far onto the airport tarmac.
  • Call of Duty: Black Ops III: The wallrun and boost jump features make it rather easy to escape multiplayer maps, but being outside the bounds for more than 3 seconds will get you killed by... something.
• Crysis:
  • If you swim out too far out, you get devoured by a huge shark.
  • There are also ships that can see you from a mile away the moment you walk out of the game's borders and fire missiles at you.
  • If you somehow avoid the shark and the enemy battleship, your own superiors will vaporize you with your suit's killswitch for straying outside the mission area.
• The Darkness: Attempting to go into the subway tunnels on foot eventually results in a train running you over. The Darkness warns you once and, if you ignore it and keep going, splat.
• Far Cry:
  • The first game has you get one-shot killed by a helicopter that appears when normal helicopters take at least four seconds of constant fire to kill you.
  • Far Cry 2: If you wander off the edge of the playing area, your character will faint from dehydration, and inexplicably wake up back within the borders of the map. If you drive off the edge in a vehicle, you'll faint, then wake up within the map's borders with the vehicle missing.
• Ghost Recon:
  • Ghost Recon: Advanced Warfighter and Ghost Recon: Future Soldier: If you go out of the battle zone, your HUD starts to get fuzzy and you're respectively told by the CO to return to battle or by a teammate that you're leaving the area of operations. Keep going, and it's Game Over.
  • Ghost Recon Breakpoint: You will get shredded by a swarm of drones if you try to leave the archipelago. This is actually justified as the same swarm of drones is why you were forced to land on the archipelago with no way out.
  • Ghost Recon Wildlands: Higher-ranked provinces are guarded by SAM sites that will shoot your aircraft down like a fly, and more heavily patrolled by Unidad forces on the ground.
• Half-Life 2: Since you can only drown if you're underwater, the game upgrades the alien leeches from the first game and places them in water near coastal areas. They start out causing little damage, but the number of leeches increases the further you swim out, creating a sort of exponential damage curve that makes it impossible for you to survive to reach the edge of the map or skip parts of the level. Since buyers of the game also gain access to the Source SDK, you can see specifically how this border patrol is managed. The entity used to enforce the border is literally called "trigger_waterydeath". In a handy bit of Script Breaking, spawning the Airboat via console allows you to avoid it entirely.
• Halo 3:
  • Some multiplayer maps have this. For example, "Sandtrap" takes place in a large desert map with no apparent barriers other than a few posts sticking up. You're more than welcome to cross past them, but once you do, explosions will start happening all around you, almost always resulting in instant death. However, if you are driving a fast enough vehicle, you can actually outrun the explosions, making for quite an entertaining race. Eventually, however, you will come across an Invisible Wall.
    • The Mythic maps added some more instances of this trope in "Sandbox". Much like "Sandtrap", obelisks will gun you down once you cross the warning borders. The only real difference is that the walls at the end of the level are visible. However, there's a hidden skull in the death zone. You can pick it up by going into Forge (the level editor) and building an explosion-proof tube. Alternatively, with practice, you can dodge the blasts while in monitor mode, allowing you to move a teleporter out to the skull for pickup after you die.
    • There's also the turrets of "Snowbound". While nowhere near as powerful as the ones in "Sandbox", they are quite deadly. Again though, you'll come across an Invisible Wall if you manage to bypass it (Hint: put a bubble shield over it or yourself).
  • Certain levels in both the campaign and multiplayer have invisible instant-kill barriers that prevent you from going out of bounds or shortcutting. Games from Halo: Reach onward have an out-of-bounds timer that requires you to "Return to the Battlefield" in 10 seconds or die.
• Serious Sam: Some levels of the first game have the player receive sunburn damage when wandering too far into the desert. In Serious Sam 3, walking too far into the Egyptian desert attracts a Sand Worm that will eat Sam.
• Soldier of Fortune: In the second game's Colombia levels, if you fall too far behind or go too far ahead of your allies, they will yell "Execute him!" and shoot you dead. Worse, there's a glitch that can get them stuck and make the level unwinnable.
• Star Wars: Battlefront has some guy either warn you that deserters will be shot (even if you're the Emperor) or just say "get back to the battle!"
• Truth About The Ninth Company reenacts a combat that took place in the War in Afghanistan. If you move too far away from the action zone and cross an invisible border, the game abruptly and summarily ends as you are court-martialed for desertion.
• Unreal Tournament 2004 will blast you with the Ion Cannon on the more open maps if you go a-wandering. The firing delay means that if you're driving a Manta flat-out, it's possible to taunt it into firing and only taking survivable splash damage.

Flight Simulators

• Ace Combat series has had some form of this throughout the series. Leaving the boundaries of the map (minus in games which on one side would let the aircraft return to base) logically result in the player abandoning the mission, with mission control asking what's wrong (resulting in Mission Failed). Almost all of them have a mission requiring the player to stay below the top edges of a canyon or some other arbitrary altitude limit, otherwise they'll be targeted by highly accurate and powerful surface-to-air missiles or a superweapon that will take them out in one hit.
  • Another one, featured more recently in the series, is the addition of that particular game's residential Rival Ace Squadron chasing after you until you successfully egress from the mission area, essentially acting as an Advancing Wall of Doom. To help encourage the player to retreat, the enemies' AI is tuned to max, fly aircraft that typically far outperform your own (and they often are in a Super Prototype or at least a real-world 4th+ Generation or higher, or have ECM jamming), and perform maneuvers you only wish you could pull off to shake off any lock on weapons, and have infinite HP on top of it should you manage to hit them anyway. The correct response is to do exactly as the game says and immediately point your nose in the direction to escape the battlefield, and hit the afterburners until you reach safety. And they tend to all focus on you specifically, meaning doing anything else will leave you constantly bombarded with incoming missile alerts.
  • Another, more realistic mission type also seen more recently is stealth-based, in which the player must avoid an enemy early warning radar network to either launch a surprise attack, perform recon for a future mission, or some other objective (like keeping a friendly plane with a malfunctioning IFF signature from getting shot down by friendly SAMs in its first appearance). The higher you fly, the more area the radars cover; flying lower lets you slip below and between the radars' coverage. Detection means game over.
• Air Force Delta: The original game features a level involving flight through a large canyon to reach the main target area; flying above the canyon's cliffs would result in a barrage of surface-to-air missiles spammed toward your plane until it's finally shot down.
• FreeSpace: Flying too far from the origin on the coordinate grid results first in a message that you are leaving the zone of engagement, then a suddenly self-destructing ship.
• Pilot Wings: "Stay Inside of Course!" If you keep going, you get "Out of Course" and fail the event.

Hack-and-Slash

• Dead Meets Lead is infamous among Steam gamers for employing malaria as a deterring agent for players who so much as stray off the beaten path.
• Jedi Knight: Jedi Academy: The mission to Blenjeel requires you to stay off the sand as much as possible, lest half a dozen sand worms immediately rush after you, any one of which can instantly eat you for a One-Hit Kill.

Mecha Games

• Armored Core, since its first iteration, lets you know helpfully where the map boundaries are, even if you do not actually possess a radar. Traditionally, the boundaries have a green line, in which crossing it triggers your onboard alarm system. Cross the red line, you fail the mission. The game treats it as if you have forfeited the mission/battle and thus kicks you out, usually with no penalties, except for storyline-important missions, which do boot you all the way back to the Title Screen. Vertical boundaries are, however, a bit vague, and getting Mission Failed from flying too high is an all too familiar problem.
  • This rears quite an ugly head in Armored Core 4, in which most of its map boundaries are too restrictive, cf., "A Swarm of Red Eyes" mission, where you have to kill mini drones by the boatload before it reaches a launch station. Not only your room to maneuver is too small, you cannot chase it all the way back to the launch station. Frustration ensues. To make matters worse, the standard double line markings are replaced by a single line, with two types of alarms. Failure to head back means instant failure, even if you edge just that slightly too far.
  • In Armored Core V, the lack of radar means the devs must denote the line somehow. The result is a very obvious yellow-and-black boundary line that kills you upon straying too far. The issue with height restrictions still plague the game, as some maps feature buildings taller than the map boundaries (Upper Area/Executive Sector is notorious for this), so continually trying to climb will result in your death. This is not to say that players don't get savvy, but the problem is there.
• G Nome: Players are restricted to within the game area by the Orbital defense kill zone. Should a player wander too far outside, a computer voice will warn the player. If the player continues, the computer will say, "Ion cannon targeting. Have a nice day.", and the player's mecha will be destroyed by a huge laser blast, presumably from a space-based weapon.
• Gundam Vs Series: Early games in the series have a border around the battlefield; crossing it gets you a warning from Mission Control ("You're leaving the mission area, return immediately!"), but if you go too far out the game takes control of your mobile suit and forces you back within the border. Making matters worse, you aren't given Mercy Invincibility during this "auto-pilot" (unless your robot was knocked down and therefore would have gotten Mercy Invincibility anyway), meaning you could very easily be attacked by enemies while it was happening. Thankfully the developers realized how annoying this all was, and the borders were replaced with Invisible Walls after Gundam vs. Zeta Gundam.
• MechWarrior: The various titles have enforced a similar system, with two lines (orange and red) visible on your radar. Crossing the orange line triggers a warning; crossing the red one triggers explodey death and often a chewing-out.
  Battlemech computer: Cowardice will not be tolerated.
• Mobile Suit Gundam 0079: Rise From the Ashes uses simple common sense: if you leave the mission area, so will your team, and the mission is aborted.

MMORPG

• Destiny: Straying from the path or lagging behind during a mission spawns nigh-unkillable high-level enemies with instant-death attacks, such as Hallowed Knights.
• The Lord of the Rings Online:
  • A temporary one can be found in the Lothlórien area. You first have to gain the elves' trust to enter their forest. If you choose to ignore the guard's warning, you get pincushioned by arrows raining from the treetops the moment you try to cross the small river.
  • There's another one on the borders of the Anduin. The only way in or out is by using boats — if you try to swim the river, orc archers on the far side will kill you dead. The boats are gated by a quest chain so that only those who buy the Mirkwood content can reach it.
  • In Angmar, there is a line of Watching Stones that applies quick-killing damage-over-time effects when you cross it. The "wall of death" was a rite of passage for many when the game was released. Like others, completing a quest line will allow you to cross the line.
• RuneScape: You can enter a dark area without a light source if you want to, but you won't be able to see shit, and you'll also be attacked by a horde of unseen tiny insects that rapidly take your health down.
• Star Wars: The Old Republic: Attempting to go outside the map boundaries results in a warning and then gradual damage, in this case in the form of a stacking damage-over-time debuff that kills you at five stacks (somewhere between ten and twenty seconds). This is occasionally justified by implying that you are heading into a lake/ocean, or that the weather is taking a turn for the worse: on Tatooine, a sandstorm kicks up, and on Hoth and Ilum a blizzard appears. In a handful of cases, it is necessary to head into these zones to find certain hidden collectibles; usually you only need to traverse a nominal strip intended to fool you into thinking there is nothing there, but at least once you need to come within an inch of your life to claim your prize.
  • In the Operation Explosive Conflict (an Operation being an instanced dungeon designed for eight to sixteen people) the group at one point needs to pass through a series of trenches as there is a full-scale battle implied to be occurring in the background. If a player should somehow scale the sides of the trench, an Exhaustion Zone warning will show — and a few seconds later the player will be killed instantly by what appears to be an orbital strike.
  • In one place in the plotline, it's actually required to go through an Exhaustion Zone to complete the plot mission. In the last main plot mission for the Imperial Agent storyline, there's an area that, when you enter it you get the "Exhaustion Zone" debuff and start to take damage. . .but the only way to complete the mission is to run through it at top speed.
• World of Warcraft uses a combination of border patrols and triggered effects:
  • Most of the coasts are patrolled by elite sharks, and if you swim past them you get a "fatigue" gauge gradually empties, like your oxygen gauge does if you're underwater, and you suffer 20% of your max health in damage every two seconds once it's depleted. The fatigue debuff is unavoidable; Even player ghosts succumb to it. There was one quest (part of the long-since defunct Scepter of the Shifting Sands quest chain) which required the player to reach an island normally inaccessible because of the Fatigue mechanic. The solution was to obtain a specific swim-speed buff to reach the island before the player died to fatigue.
  • Prior to the Cataclysm areas that had not been fully implemented would apply a "no man's land" debuff that teleported explorers out and "Guardians of Blizzard" that death-touched the over-eager.
  • Whenever a specific "enforcer" is needed in underwater areas, there is a Running Gag to use the humble whale shark.

Platformers

• Banjo-Kazooie: In Treasure Trove Cove you can kill Snacker the shark (who prefers one-liners to one-hit kills). He respawns after a short period of time, though. Treasure Trove Cove still needs an Invisible Wall, because that's one of the levels that allows Kazooie to take flight.
• Bionic Commando has a tendency to kill you with radiation if you actually try to explore the city the game takes place in.
• Conker's Bad Fur Day has a minor example of this. Trying to get inside the Wasps' hive in the Windy level before you're required to will trigger a huge, jump-scaring caterpillar-like monster to hurt Conker.
• Jak and Daxter: Each of the first three games features one: a lurker shark (pictured above), a perimeter defense robot, and a purple tentacle, respectively. The perimeter defense robot from II can be destroyed by a well-timed Dark Bomb. However, any attempts to explore further from the land will be halted by a fall into a Bottomless Pit.
• SpongeBob SquarePants: Battle for Bikini Bottom: If you go outside of the dotted line in any level or the Hub World and stay there for too long, Hans the Live-Action Hand (the one from the theme song) will come and take your character off the screen, respawning them at the start of the level or the nearest checkpoint, depending on where you were beforehand.
• Tak and the Power of Juju: The Chicken Island levels are surrounded by water inhabited by Electric Jellyfish.
• Sonic Generations: Modern Sonic can run along the surface of Seaside Hill's ocean by boosting but going too far off the main path will prompt the giant Chopper from Green Hill to snap him up after a couple seconds.

Racing Games

• Motocross Madness have a kind of invisible Border Patrol, and they come packing some serious heat. Maps are usually cordoned off within insurmountable valleys... except, for a determined player, they are surmountable. If you manage to climb up and ride more than a few feet into the vast flat wastelands outside the valley, you get blasted away by an invisible cannon, and then comically plummet back to the stage to a stock "bomb dropping" sound effect in what is arguably an instance of highly aggressive Invisible Walls.
• Splashdown features giant squids which grab your racer and fling him crashing back towards the map if you wander too far.
• Wave Race: Going outside of the boundary buoys or going out of the water will trigger a countdown. Fail to get back in bounds in time and you will get disqualified (and, if you're playing Championship Mode, a zero for the course).

Roguelikes

• Ragnarok (Roguelike): The world is bounded by an endless ocean. If you go into it, however, the world serpent Jormungandr appears and gives chase. He is lightning fast, completely unkillable, and will one-hit kill you if you come close to him or attack him (even from the other side of the screen, despite having no ranged attacks); the only escape is to rush back into the world proper before he reaches you.

Role-Playing Games

• Betrayal at Krondor has this in some places that are supposed to be inaccessible for the particular chapter you're playing. This is a case of "you can kill them, but they respawn instantly" (the game at least is fair and warns you if you click on the enemies that "there are too many of them, we can't beat them").
• Borderlands:
  • Borderlands has one consisting of a warning by the Crimson Lance, warning you that if you go any further, you WILL be bombarded. Going any further results in you losing some money and being transported to the nearest New-U Station. Many areas have impassable cliffs (up or down) to keep you in. Some also have high-powered-looking turrets with double laser sights that lock on to you if you approach the edge.
  • Borderlands 2 has the Turrets of Doom in the same way as its predecessor. It also plays with the trope a bit, with several quests which require you to grab an item placed just out-of-bounds so that you need to quickly grab it and retreat inbounds before you are instantly killed by the border turret.
• Cognitive Dissonance: The Semi-Invincible Claws in Old Saturnae. They are always in deep water, to make you have to go the long way around. If you beat one, you get a literal Bragging Rights Reward, the "Braggart's Coin" with its Flavor Text being "For those who win battles they aren't supposed to."
• Dishonored and Dishonored 2 keep the player from swimming too far away from Dunwall or Karnaca by filling the waters with aggressive hagfish.
• Dragon's Dogma and its sequel have the Brine, a blood-red mist-like mass that inhabits large bodies of water, including the ocean, and instantly devours anything that falls in — so you can forget about swimming away from Gransys or Vermund.
• Fallout:
  • Fallout: You take damage from dehydration if you wander off too far without stopping at known locations unless you carry water flasks.
  • Fallout 2 dropped the dehydration mechanic, but has powerful random encounters near late-game areas. In both games, the entire world map is accessible to you the moment you leave the starting location, so some system (easily subvertible with enough knowledge and/or luck) is necessary to prevent too early exploration and diverging from the intended path.
  • Fallout 3 features this trope when trying to get into Vault 87 — the only way there is a roundabout path through Little Lamplight. If you try to take the direct route there, you'll find out the hard way the door got hit straight-on by a nuke, and start absorbing ludicrous amounts of radiation — as high as 3,000 rads/second (for comparison, taking increments of 200 rads will weaken your skills, and exceeding 1,000 rads is fatal — meaning you can die by standing around for 0.3 seconds. This is the single most irradiated place in the whole series) It turns out that this is all for naught, too. Even if you have enough Rad-Away and Rad-X to nullify and reduce radiation, the way to your destination is blocked by an inaccessible door.
  • Fallout: New Vegas:
    • The game combines this with Beef Gates, where if you wander off the plotted line at a low level, you'll be massacred by Demonic Spiders such as Deathclaws, Cazadores, Radscorpions, or Nightstalkers.
    • The Old World Blues DLC features forcefields around the Big MT Complex that will teleport the player back if they go past.
    • In Dry Wells, unlocked by nuking Legion territory with the Lonesome Road add-on, there is a crater where one of the missiles hit; entering this area causes instant death via kill barrier (rather than near-instant death by radiation).
  • In the prologue for Fallout 4, the player will be killed by a nuclear explosion if they try to go in any direction other than towards Vault 111.
• Genshin Impact: As the game is constantly evolving, the edges of the mainland continent leading to areas that haven't been implemented yet are depicted as such on your map. If you get near one of these edges, the screen darkens and your minimap flashes red. If you don't turn around, Paimon will appear and encourage you to come back later, then your character will automatically run back.
• Horizon Zero Dawn: If you go too far into the edges of the world, the game will warn you to turn back, then automatically reload from the last checkpoint if you keep going.
• Mass Effect: If you stray beyond the boundary of the current planet you're exploring (roughly one square kilometer), you'll get a radio call from your ship's navigator that you need to turn back. If you keep going, though, you get picked up and dropped back off at the starting point.
• Paper Mario: The Origami King has a chapter taking place on the open sea. When you try to cross the map's borders, a giant Blooper rises from the sea holding a big sign with a red cross on it to tell you not to go any further.
• Risen has a sea monster appear, grab, and presumably eat the protagonist (though all you get to see is a Gory Discretion Shot in the form of a fade to black). Immediately afterwards, the protagonist respawns on the beach with no ill effects. In fact, there's even an achievement for getting caught enough times by the sea monster.
• Space Quest I: The Sarien Encounter:
  • In a desert area, there's a patrolling Sand Worm that will instantly eat you if you wander away from where you're supposed to be. Gamers who misinterpreted this as a puzzle spent some time trying to kill the sand worm by various means.
  • Go out of bounds outside the Deltaur, and the defenses will blast you into space dust.
  • Space Quest III: The Pirates of Pestulon: There's a snake that eats you if you wander off course.
• Sunless Sea: Trying to go too far in any of the four cardinal directions will trigger a horribly damaging event that will send you straight back to one of the nearest available ports. However, all four events have heavy ties with the story, and the "badges" you get (which are more like marks on your being) are necessary for the Golden Ending.
  • Try to go too far North, and you'll find out some horrendous Alien Geometries are in play; after endless days and a freezing journey that will wreak havoc in your crew, you will end up arriving at either Avid Horizon or Frostfound anyways, because there is only one way North.
  • Try to go South and you'll have to travel through Adam's Way, where the Mountain of Light's highly corrosive blood saturates the waters. Surviving requires a difficult skill check; failure means instant death, while passing it reduces your Hull and Crew to one for you to limp home. (And no, the Elder Continent authorities will not sell you a ship that can survive that - though completing the Cladery Heir's storyline might give you one.)
  • Too far to the East, and after a bit of traveling you'll be forced to turn back, as some unknowable force threatens to crush your vessel if you try to keep going. However, if you've made adequate preparations for this, the aforementioned force will let you in, triggering the path to the Golden Ending.
  • Try to go West through Barnsmore's Gap, and the Dawn Machine will Mind Rape you and your crew, forcing you to return to the Grand Geode with a massive Terror spike.
  • A variation that keeps Captains off the zee-floor when terror is too high, in the Zubmariner expansion, is the Constant Companion. It will smell your fear through the hull, will emerge from the zeefloor when you least expect it, and will chase you to the ends of the world until you surface, kill it or die. Since killing it is something reserved only to late mid-game and beyond due to its high HP and heavy damage, and it's close to impossible to battle it without taking nasty damage, it's best to just write off submersion until your terror is back under control.
• Xenoblade Chronicles 1 has nothing to limit how far you can swim in the ocean surrounding the Fallen Arm, but go too far and you'll run into Ether-polluted water that drains your health very quickly.

Survival Horror

• Resident Evil:
  • If you try leaving the mansion through the front door, you'll be stopped by a zombie dog that's always waiting there, even though you could just shoot it.
  • The Gamecube remake has one of the dogs enter the mansion if you open the front door, with several more dogs visible outside. After killing the dog that comes into the mansion, your character will refuse to open the front door again.
  • Resident Evil 2 has two instances of this. Once you have entered the Police Station property, a group of zombies will be pounding on the gate from the other side. Even if you shoot them through the bars, the game won't let you go back out because it's simply too dangerous to go back out onto the streets. Later on, you find another exit (near where you find the valve), but opening the door just lets a handful of zombies inside and won't let you open it again. The implication here is that outside that door there's just too damn many zombies.
• Slender: The Arrival: Exploiting a glitch to get out of bounds results in the message "Not even a bug in this game will save you from me", followed by Slendy teleporting to your location and accosting you, and the "I Escaped?" achievement.

Survival Sandbox

• Saurian places mosasaurs in the Inland Sea that will devour your player dinosaur if you swim too far out. (according to the developers, their role is similar to Snacker the Shark from Banjo-Kazooie.)
• Sir, You Are Being Hunted: Lingering in ponds or the ocean for too long will get you attacked by the tentacled Bog Creature.
• Subnautica:
  • The world of the base game canonically takes place entirely within a volcanic crater. Leaving the crater and entering the Crater Edge biome that surrounds the game's world will spawn up to three adult Ghost Leviathans, the second-largest hostile creature in the game. They have a different AI than the baby Ghost Leviathans encountered in the natural course of the game, will home in on the player regardless of your radiated noise level, and will immediately lose interest once you've crossed back into the play area.
  • Below Zero has a unique white variation of the Chelicerate at the boundaries of its map, serving the same role as the Ghost Leviathans from the base game. Three of them chase you until you leave the World Edge.

Text Games

• New York: Straying too far from the main area in will get you murdered.
• Zork: To prevent would-be adventurers from stumbling about in the dark, rather than finding the light source they're supposed to, the game populates dark areas with invincible monsters known as grues. The earliest versions of the game feature bottomless pits in which you can stumble. However, it's an imperfect solution as they appear in illogical areas, like a darkened attic. This is referenced in Zork Zero, the chronologically earliest game in the series, which starts out using bottomless pits, but eventually you manage to seal the bottomless pits forever — driving out the grues inside and creating an even worse menace.

Third-Person Shooters

• Gears of War: Going into dark areas gets you eaten by the Kryll (killer bats). Unfortunately, going through dark areas before the Kryll get to you is required at some points of the game.
• Helldivers 2: Wandering too far beyond the mission area and not returning in time will result in you being charged with treason and summarily executed with a Kill Sat.
  TRAITOR DETECTED
  "They abandoned our mission and our cause...execution was our only choice."
• Max Payne 3:
  • If you wander too far from your principal during an Escort Mission, a mook will pop up from nowhere and gun them down unceremoniously.
  • A similar thing occurs at the end of the first chapter, after you stop the kidnappers' van from driving away with Rodrigo, to prevent you from wandering out of the parking garage into the street. Try to do so, and Rodrigo will emerge from the van by himself and get shot by one of the kidnappers.

Turn-Based Strategy

• Star Control II has the Slylandro Probes. Although they appear throughout the game (as occasional encounters in Hyperspace), if the player leaves the Sol system before helping the starbase, they will literally swarm over the player's ship in an attempt to convince him to return to Sol. It is extremely difficult — but possible — to actually play the game like this anyway. The Border Patrol is removed once the starbase is repaired, though.

Wide-Open Sandbox

• Grand Theft Auto:
  • In Grand Theft Auto: San Andreas and Grand Theft Auto IV, players who try to skip ahead to the other cities before the plot grants them access (indicated by literal Border Patrols — the bridges to these cities will be closed off and some cops will be standing behind the boundary) will find themselves suddenly slapped with a four-star (GTA San Andreas) and six-star wanted level (GTA IV), and usually be gunned down by police and/or police helicopters shortly thereafter (I was just going for a swim, officer, honest!) They'll continue to chase you even if you go back into an open zone, but at least there you can access unlocked Pay 'n' Sprays and safehouses to help you lose your wanted level.
  • In Grand Theft Auto V flying too far out to sea, or piloting a boat too far out to sea, will cause the engine to cut out and, if in a boat, the vehicle to sink. If swimming, you are more likely to be killed by a shark than reach the map edge. Even trying cheats like Invincibility and Skyfall, you will eventually die and hit the invisible wall.
• In LEGO City Undercover, Chase McCain will be eaten by a shark if he tries to swim past the clearly visible seaweed around the islands on which the various parts of Lego City have been built. However, riding a boat lets him avoid this.
• Mercenaries: The edge of the map is designated a restricted area, and staying there too long (about five seconds) triggers a barrage of missiles from "Allied Command" that is impossible to avoid and does enough damage to kill you instantly, even if you're driving a tank when it hits. It is possible, however, to dodge the rockets. It takes a lot of luck and one of the Russian Mafia's twin-bladed combat helicopters from the second map area. You have to wait until they start firing, then spin the helicopter backward between the rockets. If you avoid them, you're free to fly until the second wave comes a few seconds later. If you survive again (say, using the godmode cheat), you'll run into an invisible wall.
• [PROTOTYPE]: Trying to cross one of the bridges to the mainland will get you bombarded by an off-screen air raid. However, trying to cross in the water will inexplicably stop your air powers from working and then jump you back to the land for no discernible reason (they give what would be a plausible reason not to be able to cross the water, but it would only make sense if the water killed you). Also, trying to use the helicopter to get out will result in a warning to turn back and then getting blown up.
  • It's possible to dodge the bridge's air raid long enough to reach an invisible wall. If you try to just swim away from Manhattan without using the bridges or vehicles, then you'll also meet with an Invisible Wall.
  • In addition, trying to get to the Reagan aircraft carrier before it comes into play in the story (only possible with a hammer throw) will lock the Reagan's rather powerful cannons on you. These knock you back substantially and will one-shot you if you don't have the upgrade that puts you in overdrive upon death.
  • The jumping happens in any deep water, for no apparent reason. It also takes the character a few seconds to jump out, even in the ponds and streams of the parks (which can't be the 30-40 feet deep that time suggests).
• Realms of Arkania: In the second game, Star Trail, you come to a large city besieged by orcs. At first, they let you approach, but will then insist on confiscating your equipment before letting you in. If you resist and choose auto-battle, the game will chastise you for thinking your small party could defeat an entire army of orcs and kill you. If you try manual combat, you'll face a huge force of wave after wave of orcs, but even if you somehow win (such as by cheating), the game will still state that you're overwhelmed and your only option is to comply or be killed.
• Red Dead Redemption II sets your Wanted Level to Maximum when entering restricted zones, resulting in lawmen shooting at you on sight. In the main story of the game, you're allowed to visit all of the states of New Hanover, Ambarino, and Lemoyne. You're allowed to visit half of West Elizabeth but not allowed in New Austin. If you manage to evade the law in West Elizabeth and make it into New Austin, an invisible sniper will One-Hit Kill you. You're free to roam the entire map in the Playable Epilogue and in the online mode.
• The Saboteur: Some borders of the map that aren't blocked by mountains or water appear striped on the map and are named 'War Zones' if you enter them. They do indeed look like battlefields, containing anti-tank barriers, scorched vegetation, and ruined buildings. Protrude too far into these zones, and fighter-bombers fly over and drop insta-kill payloads and bullets on you. This is particularly jarring because on any difficulty below 'Feckin' Hard' your character can take an inordinate amount of punishment. If you survive this (relatively simple as the bombs are inaccurate), you'll eventually meet an Invisible Wall.
• Scarface: The World Is Yours has a shark eat Tony whole if he swims too far out. Boats are easily available, though you're shit out of luck if your boat happened to explode in the middle of the ocean and you survived the blast because you knew that shark was coming...
• Spore: The creature phase includes a giant sea monster that will swallow you whole if you try to swim too far out into the ocean, even if you're flying a hundred feet above the water. There used to be a glitch where you'd start the phase in the ocean and get eaten whenever you tried to swim to land.

Other/Unsorted

• Anti-Idle: The Game: If you stay in the Dark Portal area in the Battle Arena for 10 seconds before moving to another area, The Guardian will spawn. It can instantly kill low-level players.
• Cauldron 2 has invincible lethal bats which prevent you from leaving the castle in which the game is set.
• Cholo is set in a post-apocalyptic world, and venturing into an area where the radioactivity level is too high for your shielding will cause your droid avatar to take damage over time. You guessed it: the edges of the (square) map are highly radioactive. (As a point of interest, by using the aeroplane or leadcoat droids, you can get over the edge of the map before receiving terminal damage, whereupon you wrap around and appear on the other side of the map.)
• Dear Esther has voices that whisper "come back" if you swim out to sea. You drown and respawn if you persist.
• I, Robot: Saucers patrol the edges of the shooting sections, making it a very dangerous place, should you wander there.
• LEGO Pirates of the Caribbean: Swim into areas you're not supposed to swim, and you'll get eaten by sharks or crocodiles, depending on whether you're by the sea or in a swamp, respectively.
• Might And Magic IX has an example after a shipwreck with tons of Sea Serpents that swarm you if you swim towards them, but which also shoot at you while you're at the shore, making running away the only practical option.
• Prince of Persia 2: Walking to the right on a certain screen in the first level will lead to a Sound-Only Death.
• Return Fire: If you fly your helicopter off the edge of the map, you hear a sonar sound followed shortly by a submarine surfacing beneath you, which fires a heat-seeking missile that never misses and is a one-hit kill. It can, however, be dodged infinitely.
• Seymour Goes To Hollywood: At the start, Seymour can either go right toward the studio or left into a busy road. The road is impossible to cross, until you get the lollipop item and use it to stop the traffic.
• SkiFree has extremely fast Yeti that chase after and eat you if you travel too far in any direction. Little known fact: It is possible to outrun it by pressing f.
• Steambirds has AA guns with very long range and huge damage that shoot you if you get too close to the edge of the map (though fortunately you can see their firing range).
• The Talos Principle: Approaching the end of the world (usually in the ocean) causes the display to start to fragment and glitch, with Elohim speaking a continuous Broken Record increasing in volume until the player gets too far out and is reset to the shore.
  Elohim: In the beginning were the Words, and the Words made the world. I am the Words. The Words are everything. Where the Words end, the world ends. You cannot go forward in an absence of space. Repeat. In the beginning were the Words...

Non-Video Game Examples

• Robo Rally, any robots moving off the game board are automatically eliminated by some kind of unseen mega-laser.

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