Editing Teleporter

[[File:E2m1_teleport.png|thumb|A teleporter in use on [[E2M1: Deimos Anomaly (Doom)|E2M1: Deimos Anomaly]]]]
A '''teleporter''' moves [[player]]s and [[monster]]s from one location on the map to another, almost instantly, with a flash of green fog and a whoosh noise.

Conventionally, a teleporter is constructed as a 64-[[Map unit|unit]] square with a distinctive [[flat|floor texture]]; however, this is not a technical requirement. All sides of a teleporter usually teleport to the same place, but again this is not required: some levels attempt to confuse the player by sending them to different places depending on which side the teleporter is entered from.

Doom teleporters do not conserve {{wp|momentum}} and after the player teleports, there is a delay of 18 [[tic]]s (about half of a second) before they can move again. Monsters are not affected by this.

[[Barrel]]s will also teleport if they cross a teleport line, e.g. recoiling from a shot.

If a monster or player is on the landing spot at the time of teleporting, monsters will not teleport but players will, killing whatever was on the landing spot. This is known as a [[telefrag]]. A player will self-telefrag if a [[voodoo doll]] is on the landing spot. In [[vanilla]] implementations, moreover, monsters <i>can</i> telefrag each other or the player on [[:Category:MAP30|MAP30]] of any [[WAD]] (some [[source port]]s allow the player to disable this exception or apply it to every map).

Teleporters figure prominently in [[Doom]]'s background story: it was an unexpected side effect of [[UAC]]'s experiments with teleportation that opened the gates of [[Hell]].

== Technical ==
In classic Doom, there are four [[linedef type]]s for teleporting. These implement the combinations of ''one-time'' versus ''repeating'' and ''players or monsters'' versus ''monsters only''. All of them are of the walk-over variety. Teleporter linedefs are direction-sensitive, which is necessary for cases where the landing area is another teleporter, so that the player can walk off the landing spot without teleporting again.

The linedef's [[tag]] specifies the destination [[sector]]: the lowest-numbered sector with the same tag value. Within that sector, there must be a ''teleport landing'' [[Thing]], which specifies the coordinates and [[angle]] the player or monster will have after teleporting. If there are several teleport destinations in the tagged sector (or sectors), only one will be used; the one with the lowest thing number in the sector with the lowest sector number.

[[Boom]] introduced some extended teleporter line types, including [[switch]]-activated teleporters and silent teleporters. The latter preserve player orientation, position, momentum and height so that the teleport may not be noticed; this can be used to simulate [[Room-over-room|rooms over rooms]] and for other special effects.

[[Heretic]] and [[Strife]] use teleporters in the same way Doom does. In [[Hexen]], however, teleporters are set differently. Taking advantage of the presence of a [[TID|thing ID]] in the Hexen map format, teleport destinations are given a TID and the teleport is set up to reach a random destination among those with the correct TID. Sector tags are not used.

Heretic also introduced a special decoration called teleport glitter that can be placed on the teleporter's pad. It infinitely spawns a random amount of shiny particles at floor level that rise into the air and disappear when they hit the ceiling. There are two types of teleport glitter, which differ in the color of the particles - red an blue. The red one is used for regular teleporters, while the blue one is usually only used for the exit teleporter. Hexen has a similar decoration called teleport smoke, which comes in only one variant and spawns red smoke instead of particles.

[[ZDoom]] generalized both effects by setting up teleporters with both a destination TID and a sector tag. If only the sector tag is provided, Doom behavior is used, but if a TID is provided Hexen behavior is used.

Teleport landings themselves are always invisible; the [[Doom engine|engine]] creates a separate [[mobj|object]] for the fog sprite ({{c|TFOG}}, also drawn at the departure point after the character disappears). The corresponding [[sound]] sample is {{c|DSTELEPT}}.

{{col-begin|width=auto}}
{{col-break}}
{| {{prettytable}}
!colspan="2"|Teleport landing data
|-
| [[Thing types|Thing type]]||14 (decimal), E (hex)
|-
| [[Mobj|Enum]]||MT_TELEPORTMAN<br>(Doom: 41; Heretic: 56;<br>Hexen: 226; Strife: 120)
|-
| Appears in||[[Doom]]/[[Ultimate Doom]]<br>[[Doom II]]/[[Final Doom]]<br>[[Doom 64]]/[[The Lost Levels|Lost Levels]]<br>[[Heretic]]/[[Shadow of the Serpent Riders|SSR expansion]]<br>[[Hexen]]/[[Deathkings of the Dark Citadel|DDC expansion]]<br>[[Strife]]/[[Strife: Veteran Edition|Veteran Ed.]]
|-
| Radius||20
|-
| [[Sprite]]||''none''
|-
| [[Thing types|Class]]||''none''
|-
| Flags||{{c|24}} (decimal)<br>{{c|00000018}} (hex)
|-
| Flags list|| 3: No sector links (Invisible)<br> 4: No blocklinks (Inert)
|}
{{col-break|gap=0.5em}}
{| {{prettytable}}
!colspan="2"|Teleport fog data
|-
| Enum||MT_TFOG (39)
|-
| Appears in||[[Doom]]/[[Ultimate Doom]]<br>[[Doom II]]/[[Final Doom]]<br>[[Doom 64]]/[[The Lost Levels|Lost Levels]]
|-
| Radius||20
|-
| Sprite||TFOG
|-
| Frames||12 [ABABCDEFGHIJ]
|-
| Sound||DSTELEPT
|-
| Flags||{{c|528}} (decimal)<br>{{c|00000210}} (hex)
|-
| Flags list|| 4: No blocklinks (Inert)<br> 9: No gravity
|}
{| {{prettytable}}
!colspan="2"|Teleport fog data
|-
| Enum||MT_TFOG (55)
|-
| Appears in||[[Heretic]]/[[Shadow of the Serpent Riders|SSR expansion]]
|-
| Radius||20
|-
| Sprite||TELE
|-
| Frames||13 [ABCDEFGHGFEDC]
|-
| Sound||TELEPT
|-
| Flags||{{c|528}} (decimal)<br>{{c|00000210}} (hex)
|-
| Flags list|| 4: No blocklinks (Inert)<br> 9: No gravity
|-
| Flags2||{{c|0}} (decimal)<br>{{c|00000000}} (hex)
|}
{{col-break|gap=0.5em}}
{| {{prettytable}}
!colspan="2"|Teleport fog data
|-
| Enum||MT_TFOG (224)
|-
| Appears in||[[Hexen]]/[[Deathkings of the Dark Citadel|DDC expansion]]
|-
| Radius||20
|-
| Sprite||TELE
|-
| Frames||13 [ABCDEFGHGFEDC]
|-
| Sound||TPORT1
|-
| Flags||{{c|528}} (decimal)<br>{{c|00000210}} (hex)
|-
| Flags list|| 4: No blocklinks (Inert)<br> 9: No gravity
|-
| Flags2||{{c|0}} (decimal)<br>{{c|00000000}} (hex)
|}
{| {{prettytable}}
!colspan="2"|Teleport fog data
|-
| Enum||MT_TFOG (118)
|-
| Appears in||[[Strife]]/[[Strife: Veteran Edition|Veteran Ed.]]
|-
| Radius||20
|-
| Sprite||TFOG
|-
| Frames||10 [ABCDEFEDCB]
|-
| Sound||DSTELEPT
|-
| Flags||{{c|262672}} (decimal)<br>{{c|00040210}} (hex)
|-
| Flags list|| 4: No blocklinks (Inert)<br> 9: No gravity<br>18: Partial invisibility
|-
| Flags2||{{c|0}} (decimal)<br>{{c|00000000}} (hex)
|}
{{col-end}}

{{col-begin|width=auto}}
{{col-break}}
{| {{prettytable}}
!colspan="2"|Teleport glitter data
|-
| Thing type||74 (decimal), 4A (hex) - red<br>52 (decimal), 34 (hex) - blue
|-
| Enum||MT_TELEGLITGEN (51) - red<br>MT_TELEGLITGEN2 (52) - blue
|-
| Appears in||Heretic/SSR expansion
|-
| Radius||20
|-
| Height||16
|-
| Sprite||TGLT
|-
| Frames||1 [A] - red<br>1 [F] - blue
|-
| Sound||-
|-
| Class||''none''
|-
| Flags||{{c|536}} (decimal)<br>{{c|00000218}} (hex)
|-
| Flags list|| 3: No sector links (Invisible)<br>4: No blocklinks (Inert)<br> 9: No gravity
|-
| Flags2||{{c|0}} (decimal)<br>{{c|00000000}} (hex)
|-
| Spawns||MT_TELEGLITTER (sparkle) - red<br>MT_TELEGLITTER2 (sparkle) - blue
|}
{{col-break|gap=0.5em}}
{| {{prettytable}}
!colspan=2|Teleport sparkle
|-
| Enum||MT_TELEGLITTER (53) - red<br>MT_TELEGLITTER2 (54) - blue
|-
| Velocity||0
|-
| Radius||20
|-
| Height||16
|-
| Sprite||TGLT
|-
| Frames||5 [ABCDE] - red<br>5 [FGHIJ] - blue
|-
| Sound||-
|-
| Flags||{{c|66064}} (decimal)<br>{{c|00010210}} (hex)
|-
| Flags list|| 4: No blocklinks (Inert)<br> 9: No gravity<br>16: Projectile
|-
| Flags2||{{c|0}} (decimal)<br>{{c|00000000}} (hex)
|}
{{col-end}}

== Appearance statistics ==
The Doom [[IWAD]]s contain the following numbers of teleport landings per [[Skill level#Doom and Doom II skill levels|skill level]]:

{{col-begin}}
{{col-break|width=50%}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Single-player
|-
!Game / ''Episode''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''[[Knee-Deep in the Dead]]''||''3''||''3''||''3''
|-
|style="text-align: left;"|''[[The Shores of Hell]]''||''24''||''24''||''24''
|-
|style="text-align: left;"|''[[Inferno]]''||''26''||''26''||''26''
|-
|style="text-align: left;"|[[Doom|Doom (registered)]]||53||53||53
|-
|style="text-align: left;"|''[[Thy Flesh Consumed]]''||''46''||''46''||''46''
|-
|style="text-align: left;"|[[Ultimate Doom]]||99||99||99
|-
|style="text-align: left;"|[[Doom II]]||155||156||156
|-
|style="text-align: left;"|[[TNT: Evilution]]||334||334||334
|-
|style="text-align: left;"|[[Plutonia Experiment]]||291||292||292
|-
|style="text-align: left;"|[[Doom 64]]||68||68||68
|-
|style="text-align: left;"|[[The Lost Levels]]||37||37||37
|}
{{col-break}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Multiplayer
|-
!Game / ''Episode''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''Knee-Deep in the Dead''||''3''||''3''||''3''
|-
|style="text-align: left;"|''The Shores of Hell''||''24''||''24''||''24''
|-
|style="text-align: left;"|''Inferno''||''26''||''26''||''26''
|-
|style="text-align: left;"|Doom (registered)||53||53||53
|-
|style="text-align: left;"|''Thy Flesh Consumed''||''46''||''46''||''46''
|-
|style="text-align: left;"|Ultimate Doom||99||99||99
|-
|style="text-align: left;"|Doom II||157||158||158
|-
|style="text-align: left;"|TNT: Evilution||339||339||339
|-
|style="text-align: left;"|Plutonia Experiment||292||293||293
|}
{{col-end}}

The Heretic IWADs contain the following numbers of teleport landings per [[Skill level#Heretic skill levels|skill level]]:

{{col-begin}}
{{col-break|width=50%}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Single-player
|-
!Game / ''Episode''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''[[City of the Damned]]''||''20''||''20''||''20''
|-
|style="text-align: left;"|''[[Hell's Maw]]''||''25''||''25''||''25''
|-
|style="text-align: left;"|''[[The Dome of D'Sparil]]''||''36''||''36''||''36''
|-
|style="text-align: left;"|[[Heretic|Heretic (registered)]]||81||81||81
|-
|style="text-align: left;"|''[[The Ossuary]]''||''42''||''42''||''42''
|-
|style="text-align: left;"|''[[The Stagnant Demesne]]''||''36''||''36''||''36''
|-
|style="text-align: left;"|''[[Fate's Path]]''||''3''||''3''||''3''
|-
|style="text-align: left;"|[[Shadow of the Serpent Riders]]||162||162||162
|}
{{col-break}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Multiplayer
|-
!Game / ''Episode''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''City of the Damned''||''20''||''20''||''20''
|-
|style="text-align: left;"|''Hell's Maw''||''25''||''25''||''25''
|-
|style="text-align: left;"|''The Dome of D'Sparil''||''36''||''36''||''36''
|-
|style="text-align: left;"|Heretic (registered)||81||81||81
|-
|style="text-align: left;"|''The Ossuary''||''43''||''43''||''43''
|-
|style="text-align: left;"|''The Stagnant Demesne''||''37''||''37''||''37''
|-
|style="text-align: left;"|''Fate's Path''||''3''||''3''||''3''
|-
|style="text-align: left;"|Shadow of the Serpent Riders||164||164||164
|}
{{col-end}}

The Hexen IWADs contain the following numbers of teleport landings per [[Skill level#Hexen skill levels|skill level]]:

{{col-begin}}
{{col-break|width=50%}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Single-player
|-
!Game / ''Hub''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''[[Hub 1: Seven Portals]]''||''3''||''3''||''3''
|-
|style="text-align: left;"|''[[Hub 2: Shadow Wood]]''||''2''||''2''||''2''
|-
|style="text-align: left;"|''[[Hub 3: Heresiarch's Seminary]]''||''13''||''13''||''13''
|-
|style="text-align: left;"|''[[Hub 4: Castle of Grief]]''||''5''||''5''||''5''
|-
|style="text-align: left;"|''[[Hub 5: Necropolis]]''||''0''||''0''||''0''
|-
|style="text-align: left;"|[[Hexen]]||23||23||23
|-
|style="text-align: left;"|''[[Expansion Hub 1: Blight]]''||''11''||''11''||''11''
|-
|style="text-align: left;"|''[[Expansion Hub 2: Constable's Gate]]''||''11''||''11''||''11''
|-
|style="text-align: left;"|''[[Expansion Hub 3: Nave]]''||''30''||''30''||''30''
|-
|style="text-align: left;"|''[[Expansion Hub 4: Transit]]''||''7''||''7''||''7''
|-
|style="text-align: left;"|[[Deathkings of the Dark Citadel]]||59||59||59
|}
{{col-break}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Cooperative
|-
!Game / ''Hub''!!1-2!!3!!4-5
|-
|style="text-align: left;"|''Hub 1: Seven Portals''||''3''||''3''||''3''
|-
|style="text-align: left;"|''Hub 2: Shadow Wood''||''2''||''2''||''2''
|-
|style="text-align: left;"|''Hub 3: Heresiarch's Seminary''||''13''||''13''||''13''
|-
|style="text-align: left;"|''Hub 4: Castle of Grief''||''5''||''5''||''5''
|-
|style="text-align: left;"|''Hub 5: Necropolis''||''0''||''0''||''0''
|-
|style="text-align: left;"|Hexen||23||23||23
|-
|style="text-align: left;"|''Expansion Hub 1: Blight''||''11''||''11''||''11''
|-
|style="text-align: left;"|''Expansion Hub 2: Constable's Gate''||''11''||''11''||''11''
|-
|style="text-align: left;"|''Expansion Hub 3: Nave''||''30''||''30''||''30''
|-
|style="text-align: left;"|''Expansion Hub 4: Transit''||''7''||''7''||''7''
|-
|style="text-align: left;"|Deathkings of the Dark Citadel||59||59||59
|}
{{col-end}}

The Strife IWAD contains the following numbers of teleport landings per [[Skill level#Strife skill levels|skill level]]:

{{col-begin}}
{{col-break|width=50%}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Single-player
|-
!Game!!1-2!!3!!4-5
|-
|style="text-align: left;"|[[Strife]]||149||149||149
|}
{{col-break}}
{| {{prettytable|style=text-align: center;}}
!colspan="4"|Multiplayer
|-
!Game!!1-2!!3!!4-5
|-
|style="text-align: left;"|Strife||156||156||156
|}
{{col-end}}

Of the maps covered on the Doom Wiki, the following have the highest numbers of teleport landings in single-player on skills 4-5:
{| {{prettytable}}
! Map !! Count
|-
| [[MAP05: Cosmogenesis (Cosmogenesis)]] || 785
|-
| [[MAP29: Open Your Eyes, Open Your Mind, Open Your Sectors (POOGERS)]] || 742
|-
| [[Holy Hell Revealed]] || 592
|-
| [[MAP11: Astral Sanctuary (What Lies Beneath)]] || 566
|-
| [[MAP27: Decimal Error (Slaughterfest 2012)]] || 551
|}
''This data was last verified on March 13, 2024.''

== Teleporter traps ==
Areas where the player may be tempted with pick-up [[item]]s such as powerful [[weapon]]s, [[health]], or [[armor]], or necessary progression points such as [[switch]]es and [[key]]s, may often be setup to open a door inside a remote area connected to the map by a "sound tunnel," a small thin [[sector]] through which sound can propagate, or through areas remotely joined into the same sector, within which are waiting many monsters who will then teleport close to the player or elsewhere into the map one at a time. This is often referred to as a '''teleporter trap'''. A few notable examples occur in [[Doom]] itself on [[E1M9: Military Base]], in [[Doom II]]'s [[MAP16: Suburbs]], in the [[No Rest for the Living]] expansion's {{maplinkgen|MAP01|The Earth Base|No Rest for the Living}}, and in countless [[PWAD]] levels.

== Plot details ==
{{spoiler}}
===Classic Doom===
In the backstory of [[Doom]], it is explained that teleportation research was being carried out by the Earth military inside the [[UAC]]'s bases on the two moons of Mars, [[Phobos]] and [[Deimos]]. Initial experiments consisted of throwing small objects such as tools into the "anomaly" at one site and watching them emerge from the other. Once human experiments started, however, the process was noted to have severe side effects - subjects would emerge babbling, cursing, behaving violently, and in some cases, suffering from a fate referred to as "random full-body explosion." Tests continued unabated, however, until one day a distress signal was sent down to the surface from Phobos stating that "something fraggin' evil" was emerging from the gateway. Meanwhile, Deimos had vanished from the sky completely, taking the other end of the teleportation gateway with it. After the [[Doomguy]]'s squad lands on Phobos and is promptly annihilated by the unknown invaders, the game's protagonist learns that the teleporters have opened a gateway to Hell itself.

===Doom 3===
Teleporters are much more limited in [[Doom 3]] and appear in the original campaign only within the secretive [[Delta Labs]], where they were developed based on technology reverse engineered from the remains of an ancient civilization on [[Mars]] by a team under the leadership of quantum physicist [[Malcolm Betruger|Dr. Malcolm Betruger]], despite encoded warnings against their use which were not fully understood until it was too late.

According to [[Dr. Richard Meyers]], the Delta teleporters were developed in three stages. Project Mercury, completed in 2139 as the first functioning device based on the Martian prototype found below the [[Erebus Facility]] at [[Site 1]] in 2115, was a short-range teleporter capable of moving a single human-sized subject across a test chamber to a single destination pad on the other side. The first problems with teleportation were noted immediately when one of the first few test subjects emerged on the destination pad with severe laceration injuries, which the scientists presumed must have been self-inflicted somehow, despite not understanding how such an injury could occur in what should be an immaterial state of transfer. A variable time delay in apportation was also noted, even though all mathematical models predicted that every step of the process ought to be instantaneous. A camera droid sent through at one point captured several seconds of video displaying what appeared to be a creature with numerous eyes, most likely an [[Imp (Doom 3)|imp]].

Regardless of these problems, Project Gemini was developed rapidly thereafter, consisting of several mid-range teleporters capable of moving subjects to destinations across the Delta Labs, with an additional longer-distance one-way link established to an unnamed device in the [[Phobos Labs]] facility. Accidents and oddities continued with this project, including the death of a test chimp during a routine experiment in which the device activated unexpectedly, and test subjects began to manifest severe psychological and physiological deterioration, including ravings about Hell and demons, speaking in tongues, self-mutilation, an unrecognized progression toward [[zombie|zombification]], and in many cases, suicide.

Despite the now obvious dangers, Dr. Betruger's unrelenting obsession with the dimension to which the teleporters seemed to connect led to the development of Project Apollo, a room-sized teleporter capable of moving whole teams of people and sizable devices and equipment into the other dimension for purposes of exploration and capture of specimens. The energy and data processing requirements of this device drove the [[Mars City]] base into a state of disarray, as equipment across the facility malfunctioned or could not be used effectively. Many teams began teleporting into the other dimension on a regular basis, and many never returned at all. It was at this time that people across the Mars base also started to be affected by strange visions, auditory hallucinations, gruesome and usually fatal accidents, and unexplained fugues during which they would violently attack their coworkers.

Still unsatisfied, Betruger also initiated the development of another powerful device in its own entirely new research facility, the top-secret [[Exis Labs (Part 1)|Exis Labs]], which would be capable of bi-directional teleportation of large devices such as rovers and even drop ships. To complete the bi-directional capability, a matching device was built in Hell, within the remains of an [[Hell Outpost|outpost]] built there by the [[ancient Martian civilization]]. Though incomplete as of the time of the invasion of Mars City by the demons, this device was recognized as a possible threat to Earth once Dr. Meyers understood Betruger's intentions, and he set out to destroy it.

Unable to wait any longer in his evil plans in concert with the demons, who had offered him unlimited power in exchange for enabling them to reach Earth, Betruger used the Delta Apollo teleporter to unleash an invasion of the Mars base by taking the [[Soul Cube]] through the portal on an unscheduled trip. For reasons not fully explained, this device being taken to Hell caused the portal to remain permanently open, enabling a massive invasion.

===Doom (2016)===
In [[Doom (2016)]], the mechanisms behind teleportation are evidently well understood by the UAC, but these are never detailed in the game. Beginning in 2145, the UAC began both manned and unmanned expeditions into Hell known as the Tethering Operations. These expeditions had the primary goals of retrieving artifacts and creatures through use of a technology known as the [[tethering device]], a sort of interdimensional beacon that enables retrieval of objects from other dimensions even when a freely open portal is not available.

The UAC is evidently capable of sustaining various types of interdimensional portals, as devices in the [[Argent Tower]] and the [[Lazarus Labs]] are both referred to using this name. The former was a carefully regulated rift which enables the UAC to sap Hell's infinite [[Argent energy]]. The latter was apparently primarily used for the Tethering Operations, until [[Dr. Olivia Pierce]] used it to unleash a Hell wave which destroyed the entire facility.

Breaching containers of highly concentrated, unrefined Argent energy can cause temporary rifts to form, teleporting nearby people and objects into Hell. In [[Doom VFR]], [[Dr. Peters]] is also capable of creating such a temporary rift by simultaneously firing all of the prototype [[BFG-9000 (Doom 2016)|BFG]]s, as that gun is also based on Argent power.

The [[personal teleporter]] allows short to medium range teleportation in the form of a hand-held, throwable device in multiplayer.

Several demons possess natural teleportation abilities in the continuity of Doom (2016) and Doom Eternal: the [[summoner]], [[prowler (Doom Eternal)|prowler]], and [[Arch-vile (Doom Eternal)|arch-vile]]. In the case of the summoner and prowler (which had super-speed in its previous [[Prowler|incarnation]] instead of teleportation) it is unknown if it is actual teleportation or a "phase shift," making the demon move at a high speed, unseen and invisible. 

Doom VFR also introduces a short-range teleportation capability for rapid movement through the {{wp|virtual reality}} environment. Use of this feature teleports Dr. Peters' cybernetic body to the location where the targeting reticle appears. Interestingly, the target has the appearance of a pentagram, suggesting that this form of teleportation is based on demonic principles (possibly related to the abilities of the [[summoner]] or [[Arch-vile (Doom Eternal)|arch-vile]]).

===Film===
In the {{timeline|2005}} [[Doom movie]], a teleportation device called the '''Ark''' was discovered on Earth in 2026 and was moved by the government to a facility at {{wp|Area 51}}. It was discovered to control a wormhole, with the other end exiting at an ancient city on Mars. It proved useful for accomplishing instantaneous interplanetary travel, and was used to move supplies and personnel to and from the UAC base at [[Olduvai]]. It becomes a danger to Earth after experimentation with an ancient Martian retrovirus goes out of control, spawning demon-like monsters who spread the infection to others while killing and maiming. Marcus "Pinky" Pinzerowski's refusal to destroy the Ark, the study and operation of which he dedicated much of his life, allows the monsters to threaten Earth. It is ultimately destroyed by [[John Grimm (Reaper)|John Grimm]] at the end of the film, when he tosses a grenade through it to kill [[Asher Mahonin (Sarge)|Sarge]].

The Ark portal appears like a large levitating watery ball while the device is active, expanding to fill the platform and then receding and vanishing afterward. Instability during its early operation was responsible for the loss of Pinky's legs.

The {{timeline|2019}} film ''[[Doom: Annihilation]]'' also retains the teleportation plot element, with the gates from the original backstory being featured as existing on Phobos and on Earth, and believed to have been left behind by an ancient civilization. As in the games, it is initially unknown that the gates lead to Hell. An invasion of the Phobos base occurs after [[Malcolm Betruger (Doom: Annihilation)|Malcolm Betruger]] sends himself through the gate.
{{endspoiler}}

== See also ==
* [[Final Doom teleporters do not set Z coordinate]]

[[Category:Doom engine]]
[[Category:Gameplay]]
[[Category:Plot elements]]