This article is about the Half-Life: Opposing Force enemy. For the enemy cut from Half-Life 2, see Alien Assassin, also known as a Shock Trooper.
Shock Troopers are one of the main Race X species that invade the Black Mesa Research Facility during the later stages of the Black Mesa Incident. They act as one of the antagonist forces of Half-Life: Opposing Force. One is first briefly glimpsed in the chapter "We Are Pulling Out", and they start to appear as common foes beginning in Crush Depth.
Shock Troopers are bipedal creatures with four arms and a plate-like body covering resembling an insect exoskeleton. Most notably, they have a single large eye centered in their torso. Shock Troopers are highly intelligent creatures, making up the primary work force and military component of Race X. They have mastered teleportation technology, an ability they managed to develop innately, and use it to teleport in and out of combat situations. They also control the teleportation of both the Pit Drones and the Voltigores. At one point, Adrian Shephard observes a Shock Trooper grabbing a Black Mesa scientist prior to teleporting away, abducting him in the process.
They carry creatures known as Shock Roaches, parasites which must attach themselves to hosts in order to survive. The two share a symbiotic relationship. These Roaches are, in turn, used as weapons to discharge deadly bolts of electricity at foes rapidly. Shock Troopers also have the ability to spit up Spore Pods, biological explosives which they throw at enemies like grenades. At close range, they punch hostiles to knock them back. When alone, a Shock Trooper will often summon Pit Drones to assist him in battle. However, Shock Troopers also frequently travel in groups, working closely with their teammates to outmaneuver their enemies.
 Infant version
Baby Shock Troopers, named Spore Launchers in-game, are the young larval stage of Shock Troopers that has only formed a head and torso with multiple tails trailing behind it, effectively a tadpole. They are amphibious, although immobile outside of water. Infant Shock Troopers are first found in Black Mesa being kept in water tanks in the Biodome Complex of Sector E, seemingly implying that the Black Mesa Science Team had encountered and taken interest in studying Race X specimens in addition to Xen creatures.
This alien can be used as a weapon, allowing itself to sit on the user's shoulder and wrapping its tail around his or her arm. The user holds one of its pair of appendages near its mouth, those resembling insect mandibles, as a handle. Baby Shock Troopers are capable of firing baseball-sized biological spores collected from pods scattered around the facility which are then hand fed to the creature and launched either as rocket or grenade-like projectiles, both very toxic to enemies. Adrian Shephard demonstrates some fondness for this creature as he is seen occasionally petting the alien's head gently, to which it responds with affectionate purrs.
 Behind the scenes
An early rendition of the Shock Trooper depicted the alien with orange skin. Before the recording sessions, Gearbox's lead programmer John Faulkenbury and sound designer Rob Heironimus implemented Greedo's voice from Star Wars as a placeholder for the Shock Trooper's sounds.
Shock Troopers inherit the same artificial intelligence behavior and tactics used by the HECU Marines from the original Half-Life. They were modified not to recognize the aliens from Xen. However, they will still attack Alien Grunts[i] and Gargantuas on sight. This is believed to be an error in the code as the developers did not disable the Marines' "nemesis" function which overrides their AI. This function makes Shock Troopers ignore the player and solely target their specified nemeses, in this case the ones attributed to the Marines.
Shock Troopers possess a verbal form of communication, uttering strange electronic-sounding noises to each other. Their language consists of 17 distinct phonemes which are combined to form the phrases heard during combat. This is the full list of phrases and meanings:
- "Ksswirtras" - an alert when throwing a spore grenade.
- "Ksskyurkiml" - a warning shout when reacting to an incoming grenade.
- "Ditdit", "Ditksskss", "Kssdit ditkss" - said when a human is spotted.
- "Purthirvpurksskss" - said when a hostile alien is spotted.
- "Kagablisbliska" - said when retreating to cover.
- "Kimlkiml" - a taunt.
- "Mubpuhmubditdit" - said when charging the enemy.
- "Kukurku" - an idle statement.
- "Puhpurhyuka" - a question spoken to other Shock Trooper members.
- "Dupdup" - a response given to questions.
- "Ksskss" - asking other members to check in.
- "Dupblisdup" - a checking in response to acknowledge that the area is clear.
 List of appearances
- Half-Life: Opposing Force (First appearance)
- ↑ 1.0 1.1 Stephen Bahl as quoted on Marc Laidlaw Vault on the ValveTime.net Forums
- ↑ .plan file of Brian Martel on Blue's News (September 7, 1999)
- ↑ 3.0 3.1 3.2 3.3 3.4 Half-Life: Opposing Force Prima Guide
- ↑ Game Spin: Half-Life Expansion on Gamecenter (June 18, 1999) (archived)
- ↑ .plan file of Randy Pitchford on Blue's News (August 2, 1999)
|Creatures||Gene Worm · Pit Drone · Pit Worm · Shock Trooper · Sprite · Voltigore|
|Weapons||Shock Roach · Spore Launcher|
|Technology||Teleportation · Transportation · Weapons|