{{Enemy Infobox
| image=FileStrider crouched.jpg|250px|
| name=Strider
| affiliation=Combine
| type=Heavy assault Synth
| health=*5 (Easy), 7 (Normal), 7 (Hard) Rocket-Propelled Grenade Launcher (Half-Life 2)|RPG hits''https// Valve Developer Community
* 6 (Easy), 10 (Normal), 14 (Hard) Energy Ball hits
| weapons=*Pulse cannon
*Warp cannon''Half-Life 2 Prima Guide''
*Spiked limbs
| entity=npc_strider
| designer=*Ted Backman (appearance)
*Bill Fletcher (animations)''Half-Life 2 Raising the Bar''
*Tom Leonard (artificial intelligence){{LI|pub/tom-leonard/0/86b/493}}
{{Quote|Oh my God... Striders really tore the hell out of this place...|Alyx Vance|Half-Life 2 Episode One|Fileal plaza view.ogg}}

The '''Strider''' is a large tripodal Combine Synth introduced in ''Half-Life 2'', often acting as a sub-boss.


The Strider's body is that of a brown colored beetle-like carapace mounted on three jointed legs, with a turret below the thorax. The Striders serve as the Combine's main heavy ground assault unit.

The three long legs of the Striders are tipped with sharp spikes, for impaling targets and clearing debris. This also serves as a defense to what is commonly a weak point for creatures, the underbelly.

While walking about or attacking, Striders produce a host of different electronic sounding vocalizations, such as growls, groans, whoops, and howls; when killed, they give a mournful cry. In addition, Striders will leak a yellowy substance when damaged, and apparently contain a biological cerebral unit that looks very much like a human brain (although considerably larger), providing evidence to the Synth being a fusion of living flesh and machine (so far, the Strider is the only known Synth to possess any "organ" at all).

FileStrider rubble C17.jpg|250px|thumb|left|Strider among City 17 rubble.

The Strider is an excellent example of the use of assimilated or created creatures to control the population. Its huge size and accurate weapons make it ideal for slowing revolutions and preventing a large-scale uprising.

Individual Striders are often used to patrol off-limits City 17 streets and provide heavy support for groups of soldiers. However, in full-scale military combat, Striders are used instead as heavy artillery to destroy all structures in an area as a means of removing all entrenched hostile forces. Striders fit both roles well due to their various weapons and remarkable maneuverability on even the harshest terrain (considering they are tripods, and extremely large). Despite their height, Striders can crawl through tunnels to chase enemy combatants and "dig" through underground obstacles using their warp cannon. 

In wilderness areas, Striders are often accompanied by Hunters which act as escorts to destroy smaller targets. During the Combine offensive against White Forest, Striders are used to destroy the outer buildings surrounding the Resistance base, including the Magnusson Device teleporters. To provide better situational awareness and spot targets (particularly in urban or close country environments), Scanner Type 2|Scanners may accompany individual Striders and search out areas the Strider cannot easily see into.

Striders may also be transported to and from combat zones by Combine Dropships. When being transported they will fold their legs into a compact shape that allows them to be carried.

As seen on the newspaper clips found at Black Mesa East, Striders apparently took part in the Seven Hour War, as one can be seen right of the WikipediaUnited Nations Headquarters|United Nations building, though its size is larger than it should be.


Besides impaling targets with their long legs, Striders are also armed with two ranged weapons. The first is an anti-personnel pulse cannon mounted between a pair of compound eyes on the front of the Strider's carapace. The second (and by far the more powerful) weapon is a warp cannon mounted on the Strider's belly. This cannon not only causes scenic destruction but also inflicts massive splash damage that will vaporize anything in proximity to the area of impact. Prior to the warp cannon's discharge, a thin blue laser indicates where the Strider is aiming and the air surrounding the cannon's barrel will be distorted by a blue aura.

In ''Half-Life 2'', the Strider's pulse cannon does a large amount of damage - approximately 20 to 30 per shot. However, it is programmed to only hit with the last few shots, giving the player time to seek cover. In ''Episode One'', the Strider's pulse cannon is far more accurate and has a faster (but variable) rate of fire, but in order to balance gameplay, inflicts a fraction of the damage (approximately 5 to 10).


===''Half-Life 2''===
FileD3 citadel 020045.JPG|thumb|right|200px|Striders walking in the Citadel.

In ''Half-Life 2'', the Strider is first glimpsed walking along a barred street with a City Scanner some time after leaving the City 17 Trainstation|Trainstation Plaza.

The Strider is seen again much later in the game, during the chapter ''"Follow Freeman!"'', during the Overwatch Nexus battle. There Gordon must defeat several Striders, helped by other Rebels, firing with their RPGs from the ground and the roofs. Soon after, a Strider confronts Gordon who tries to hide in a building. This is where the Strider is seen working with Shield Scanners that always reveals Freeman's presence to the tripod wherever he tries to hide.

Right after that building, Gordon finds himself into another battle and must defeat Combine soldiers and Striders with other Rebels. After defeating all Striders, Gordon reunites with Barney Calhoun|Barney and Dog and enters the Citadel.

Within the Citadel, Freeman sees walking Striders ready to be released on the field, and fights one some time later.

===''Half-Life 2 Episode One''===

The first ''Episode One'' Strider is seen by Gordon and Alyx inside the Citadel when a Dropship carrying a Strider takes off just beneath them and crashes.

The next one is seen when they leave - at last - the City 17 Underground and see that Kleiner has taken over the Breencast network. There a Strider is seen from afar walking among rubble and does not notice the two characters. The comment ''"Oh my God... Striders really tore the hell out of this place..."'' by Alyx suggests that Striders are responsible for most of the destruction made to the city.

Later at the Technical Trainstation a Strider and several Overwatch Soldiers attempt to prevent Gordon and Alyx from leaving the city, the Strider acting as the game's final boss. The player will be required to hit this Strider with seven Rocket-Propelled Grenade Launcher (Half-Life 2)|RPG rockets, in any difficulty mode. After successfully defeating it, Gordon and Alyx finally leave City 17 via train.

===''Half-Life 2 Episode Two''===
FileDog vs Strider Outlands.jpg|thumb|right|250px||Dog about to prove his value against a Strider, as seen in the ''Episode Two'' trailer.

In ''Episode Two'', Striders are first seen among a Combine convoy walking to White Forest.

Some time after, at a short distance from White Forest, Gordon and Alyx's way are barred by an apparently dead Strider. It suddenly wakes up, but Dog emerges from the the forest and jumps at it. A spectacular battle ensues, ending when Dog rips open the Strider's head and removes the creature's brain.

Striders are last seen during the White Forest battle, where they threaten the rocket's launch, aided by Hunters. To defeat them, Gordon must use the Magnusson Device, or Strider Buster, introduced by Arne Magnusson. It is to be thrown at the Strider's main body with the Zero Point Energy Field Manipulator|Gravity Gun, then detonated by shooting at the device with any firearm. During the battle, it is possible for the Striders to destroy many of the surrounding buildings. After Freeman has taken them all down with the Strider Buster and the help of the other Rebels, the rocket can be successfully launched.


*Striders tend to follow specific patrol routes when tasked with defending a certain area, making them fairly easy to avoid. However Shield Scanners sometimes accompany them, functioning as spotters for the Strider, searching inside buildings and other places of concealment for targets the tripod would otherwise be unable to see. However this symbiont behavior between the two Synths is only seen after the Overwatch Nexus battle.

*Due to their incredibly high damage output and pinpoint accuracy on their last few hits, cover plays an extremely important role while fighting Striders. Often, instead of fighting in the open, one is much less likely to die while only running out of cover when running to another spot or when launching a rocket.

*Striders are often rather unaware of their opponents - this is most obvious during the battle outside the Overwatch Nexus. This can be exploited to avoid a lengthy and hazardous battle against many partially avoidable Striders, since when only one or two Striders remain, they can be bypassed.

*After the Magnusson Device, the most powerful weapon against Striders, the Rocket-Propelled Grenade Launcher (Half-Life 2)|RPG is the most efficient weapon, as its rockets do the most damage, though it takes up to 7 rockets just to kill one in Normal mode. Fragmentation Grenade (Half-Life 2)|Grenades, Submachine Gun (Half-Life 2)|Submachine Gun grenades, and Overwatch Standard Issue Pulse Rifle|Energy Balls do about half the damage of a rocket. Unlike Gunships, Striders tend to ignore all projectiles launched at them, focusing on attacking the player instead.

*Using the Magnusson Device against a Strider is not advised until all nearby Hunters are defeated, as they will fire at the device as soon as they see it.

*On harder difficulties, Striders tend to duck from flying rockets, which should be anticipated when firing.

*It is advised to fire rockets aimed at the "knees" of the Strider. The explosion will severely cripple the Synth, slowing down its movements.

==Related Achievements==
{|class=wikitable style="vertical-aligncenter;" width=100%
!colspan="2" style="text-alignleft"|''Half-Life 2''
|rowspan=2 width=64px|FileHl2 beat c1713striderstandoff.png
!style="text-alignleft"|''Giant Killer (10G)''
|Survive the rooftop Strider battle in the ruins of City 17.
!colspan="2" style="text-alignleft"|''Half-Life 2 Episode Two''
|rowspan=2 width=64px|FileEp2 beat outland12 nobuildingsdestroyed.png
!style="text-alignleft"|''Neighborhood Watch (35G)''
|Save all buildings outside the missile silo from destruction.
|rowspan=2 width=64px|FileEp2 beat game.png
!style="text-alignleft"|''Defensive of the Armament (20G)''
|Save the missile silo from the Combine offensive.

==Behind the scenes==
FileStrider early5.jpg|thumb|right|200px|Concept very similar to the final version, dated 2001.

*Valve's Bill Fletcher used a giraffe/gorilla combo as animation reference for the Strider. He wanted the creature to capture the gracefulness of a giraffe and stomp and lead with its elbows like a gorilla when it walks, to convey a simian power.

*At some point in ''Half-Life 2''’s development, the Strider was white, like the Combine Super Soldier, the Combine Assassin or the Overwatch Elite.

*Early concepts depict the Strider with different heads, such as one only consisting of a cannon.

*Several early iterations also bore miscellaneous markings, notably a maroon circle with a "Z" or a lightning bolt in the middle, and some sort of L with a small dot in the opposite angle.

*It was originally to be met in the Coast levels, at least near the Air Exchange.

*According to one of the concept art pictures featured in ''Raising the Bar'', the Strider's current design was already defined as early as in 2001 (as seen in the date in Ted Backman's signature).

*A seen in the Development of Half-Life 2 game|''Half-Life 2'' leak source code, the Hopwire Grenade was originally to be the weapon of choice against Striders,Development of Half-Life 2 game|''Half-Life 2'' leak source code replaced in ''Episode Two'' by the Magnusson Device. This is confirmed in the ''Episode Two'' commentary, in which Valve's Joshua Weier states that the Magnusson Device "started life as a ''Half-Life 2'' weapon called the Hopwire".''Half-Life 2 Episode Two'' commentary

*As seen in the playable Development of Half-Life 2 game|''Half-Life 2'' leak, it was at some point possible for the player to assault Striders, ride them and take their gun after killing them. Noclipping to the Strider's head, then pressing the Use key results in the player seeing through the creature's eyes. At that point the only thing to do to free oneself is to kill the creature, for instance with the RPG (as the only way to kill a Strider in the playable ''Half-Life 2'' leak is by standing inside its head), or reload the game. When killing it, the Strider collapses, releasing the player. At that point, the red ERROR model appears. When walking through it, the player acquires the Immolator. This suggests the Immolator acts here as a placeholder for the Strider's warp cannon, and that resuing it was at some point considered, a role that the Combine Guard Gun was already filling. As a side note, the Immolator worldmodel exists and should appear instead of the ERROR model.

*The Strider appears in several E3 demonstrations "Strider" (2002), "Kleiner's Lab" (2003) and "Striders" (2003). In "Strider", several Striders chase gas mask Rebels through ruined streets, and one of the Striders destroys an arch building. In "Kleiner's Lab", a Strider interrupts a conversation between Alyx and Kleiner in the latter's lab. "Striders" feature the 2002 demo in a more recent setting.

*The Strider is an indirect successor to the Combine Super Soldier.

*The cut Combine Guard Gun is a similar weapon to the Strider's cannon (it was also to be used against Striders, according to the leaked game source code); the cut Vortex Hopwire also produces similar effects. The cut Black Hole Gun, originally designed for ''Quiver'', is also similar.

FileDog challenge.jpg|thumb|left|250px|Dog challenging the Strider in the ''Episode Two'' trailer.

*In the ''Episode Two'' commentary, information is given about the spectacular battle between Dog and the Strider
**According to Valve's Ken Birdwell, the Strider for that sequence was custom built and, with big parts of it being ripped off and "goo" being spewed everywhere, was used as a test bed for new modeling technology and Valve's new particle system introduced in ''Episode Two''. He further adds that with their episodic process, a lot of new technology comes online throughout development. Since any new technology takes a year or more to really work out all the bugs, they like to look for isolated areas - like this one - where they can test out new things without risking all the things they already know work. They did the same thing with HDR in ''Lost Coast''; once they are sure they did not break anything, they can move the features back into general use. Since this consider the Strider has worked out really well in that sequence, it will be the new Strider as they move forward, and they will be applying what they have learned to any new monsters in ''Episode Three''.
**Bill Fletcher adds that their main goal with that scene was to create "a cinematic battle of the titans", Dog vs. a Strider. While they were excited with the early implementations, it became obvious that players were uncertain of their role in the scene. Originally the confrontation built slowly with Dog squaring off against the Strider, but having such a slow beginning proved problematic. It looked good in the ''Episode Two'' trailer, but did not play well in the game. Instead of the slow build, the team decided to send Dog straight into action. He makes a grand entrance, jumps on the Strider and the fight begins. The quick start helps to grab the players attention instead of giving them too much time to worry about what they should be doing.

*According to John Guthrie, the massive Strider battle near White Forest was in production longer than any other map in ''Episode Two''. Tuning it required many, many months of testing and iteration to address playtest feedback, and this was complicated by the fact that every time the team playtested, they saw individuals adopt completely different approaches to defeating the Striders. Some threw logs at Hunters; others relied on their Rebel companions to kill them. Some players never sprinted, while others never used the car. They tried to keep supporting all the different strategies that occured to players, so that their experiments with tactics would be rewarding rather than frustrating. Meanwhile, they had to make sure the Strider and Hunter behaviors were consistent, and balance the experience so that it would be a satisfying game experience for all different play styles at every skill level.

*According to a comment section in ''Half-Life 2'''s source code, the Strider originally had a bug where its pulse cannon's damage per shot to NPCs was based directly on the ammo capacity (15), when it was assumed that original damage was 8. This was fixed in an update and finally fixed in ''Episode One''. When shipping ''The Orange Box'', the Strider's ammo was changed to 15 for ''Half-Life 2'' and 5 for ''Episode Two''.''Half-Life 2'' source code

FileE3 Strider.jpg|thumb|right|200px|Gas mask Rebels fleeing a Strider in the map "e3_strider", in one of the earliest ''Half-Life 2'' screenshots.

*The only way to spawn a Strider via the console is to activate "noclip", go up to at least the creature's height, and type into the console "give npc_strider". It will not use its warp cannon and will only walk if the target moves out of its line of sight and if the map has the necessary node structure.

*Striders closely resemble the "tripods" described in WikipediaH.G. Wells|H.G. Wells' ''WikipediaThe War of the Worlds|The War of the Worlds'', especially the warping cannon, which is much similar to the WikipediaHeat-Ray|Heat-Ray from the aforementioned novel. Earlier Strider concept art further exemplifies the similarities.

*The accuracy and rate of fire of the Strider's pulse turret was increased in ''Episode One''.

*The Strider has a strange method of firing with its pulse cannon, a variation of ''walking'' (that is, firing at a point near a target and slowly aiming towards it). It seems that when it focuses on a particular enemy, it fires a long string of shots the first ones do not hit, but unless the enemy goes behind cover, the last few will ''always'' hit. However, this has been removed in ''Episode One'', notably in the final Strider battle.

*Gunships and Striders bear the same logo on their back and head, respectively. This logo was on the back of the Overwatch Soldier's old skin (in white) and can also be seen on the shoulder of FileCombine Synth Elite Soldier2.jpg|one of the Combine Synth Elite Soldier versions. Its meaning and whether it is a Combine logo or not or if it proves a closer relation between the Gunship and the Strider are unknown.

*The Strider is referred to as "he", not "it" by Valve employees.

*If a Strider gets close enough to the antenna outside White Forest, it will destroy the antenna in a single shot with its warp cannon. Afterwards, the message "The rocket has been destroyed – Magnusson's misgivings about the Freeman are completely justified – The game now ends" is shown, and the most recent save loads.


===Concept art===

FileStrider heads.jpg|Studies of different heads.
FileStrider early4.jpg|Early Strider, with the head only consisting of a cannon.
FileStrider early2.jpg|Ditto, showing a cream-white body with red markings.
FileStrider early1.jpg|Ditto.
FileStrider early3.jpg|Another study with the body and the head clearly divided.
FileStrider early5.jpg|Concept very similar to the final version, dated 2001.
FileStrider head symbol rtb.svg|Head symbol featured in the previous image, and the third of the gallery.
FileStrider secret.jpg|Model render.
FileDog vs Strider poster clean.jpg|Dog vs. Strider poster.



FileEnd strider.png|''Half-Life 2'' leak texture based on a Strider screenshot, used in the E3 2003 video "http// Psyche" and the ending sequences of the WC mappack maps "e3_end" and "hazard01".
FileStrider arch oicw.jpg|Strider attacking the player in the E3 2002 demo "Strider".
FileStrider attack pre-release.jpg|Strider in the E3 2003 demo "Striders".
FileStrider E3 lab.jpg|Strider in the E3 2003 demo "Kleiner's Lab".
FileSky walk0013.jpg|Strider in the ongoing battle at the foot of the Skyscraper, Vertigo version.
FileE3 strider ride.jpg|Riding a Strider in the map e3_strider.
FileE3 strider immolator error.jpg|The Immolator worldmodel error after killing a Strider in the map e3_strider.
FileE3 strider immolator.jpg|Getting and testing the Immolator in the map e3_strider.

====''Half-Life 2''====

FileStrider logo.png|Head logo.
FileStrider pulse cannon.jpg|Detail of the Strider's pulse cannon.
FileStrider warp cannon.jpg|Detail of the Strider's warp cannon.
FileStrider hit.jpg|Strider being hit by bullets.
FileStrider fire.jpg|Strider firing.
FileD3 citadel 040291.JPG|Strider and Combine soldiers attacking Freeman in the Citadel.

====''Episode One''====

FileEp1 c17 060005.JPG|The Strider looking for Gordon in the Technical Trainstation.
FileEp1 off screenshot 2.jpg|The Strider firing at Gordon in the Technical Trainstation.

====''Episode Two''====

FileDog challenge strider legs.jpg|Dog challenging the Strider in the ''Episode Two'' trailer. 
FileEp2 outland convoy.jpg|Combine convoy in the Outlands, among them Striders.
FileEp2 outland 05004406.jpg|Detail of an Advisor Platform, with a Strider on the left.
FileMagnade training2.jpg|Dead Strider used for Magnusson Device training at White Forest.
FileMagnade training view.jpg|Ditto.
FileEpisode2-strider.jpg|Strider during the White Forest battle in the second ''Episode Two'' teaser.
FileStrider about to fire trailer.jpg|Strider about to fire on the lodge near White Forest in the ''Episode Two'' trailer, distorting the view around it.
FileStriderBusterKill.jpg|A Strider being destroyed by a Magnusson Device.
FileWhite forest fail.jpg|Strider destroying White Forest's antenna if Gordon fails to defeat all the Striders.
FileStriderBusterPlans.jpg|The written instructions on how to use the Magnusson Device against a Strider.
FileStrider inside.jpg|Inside the Strider ripped open by Dog, with the brain visible.
FileStrider brain model.jpg|Strider brain model.

==List of appearances==

*https// ''Half-Life 2'' - E3 2002 Trailer {{1st}} {{Nc}}
*''Half-Life 2''
*''Half-Life 2 Raising the Bar''
*''Half-Life 2 Episode One''
*Source Particle Benchmark {{Gf}} {{Nc}}
*''Half-Life 2 Episode Two''


CategoryCombine units
CategoryHalf-Life 2
CategoryHalf-Life 2 Episode One
CategoryHalf-Life 2 Episode Two
CategoryTed Backman designs