Arc Thrower (EU2012)

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Project Spark Results
Arc Thrower Research

We've completed our research into the Arc Thrower prototype and we believe this device is ready for final production in Engineering. The mechanism functions on the basic premise of neurological disruption, emitting a focused electromagnetic pulse capable of confusing and incapacitating targets within a limited range. As this is our first venture into the field of non-lethal weapons based on the alien physiology, it's safe to assume there may be unexpected results in the field. It's very likely that some aliens will resist the disabling effects of the weapon, in which case it might be more effective to weaken the enemy first. The Arc Thrower is also constrained by our current power supply technology, which limits its effectiveness to two shots per deployment. Any captives retrieved from the field will have to be housed in an Alien Containment facility; I strongly advise we build that facility before attempting to capture live specimens.

Source: XCOM: Enemy Unknown (2012) Research Archives

Arc Thrower

The Arc Thrower is a non-lethal sidearm designed to stun hostile targets. The mechanism seems to be most effective against weakened enemies.

  • A nonlethal weapon that can stun enemies
  • The chance of a successful stun is much greater if the target has low health
  • Does not affect robotic enemies
  • Advanced versions have a better chance to stun, can heal friendly SHIVs, and take control of certain enemies
Source: XCOM: Enemy Unknown (2012)


Research Required Xeno-Biology
Base Costs §35
5 Engineers
Abilities/Stats Stun

"I trust you have tested this thing..." - Shaojie Zhang

The Arc Thrower will be one of your first plot-centric fabrications; and like the various stun devices in previous iterations of XCOM, it may actually be the most important weapon in your arsenal against the alien invaders. Not also is it needed to move the story along, but the weapon drops from captures, and the results from interrogations will vastly expand the potency of XCOM. Off-the-shelf, it costs a maximum of 35 credits (the first handful of Engineers you receive will easily drop it to the mid-low 20s), and holds a charge for two stun attempts, but even then only if the target has 4 or fewer health remaining (49/70/80/90% on 4/3/2/1hp). Its main drawback is an extremely limited range, barely safer than the old touch-range Stun Rod, that usually extends to 3 squares from the target alien.

  • Foundry Upgrades:
    • Improved Arc Thrower: increases effectiveness to enemies with up to to 7hp (49/70/80/90% on 7/6/5/4hp and 95% chance on 3hp or lower).
      • Requires: Elerium research, 4 Drone Wrecks, 20 Weapon Fragments, 10 Engineers.
    • Drone Hack: Take control of an enemy Drone for combat (similar to Mind Control).
      • Requires: Drone Autopsy, 4 Drone Wrecks, 20 Weapon Fragments, 10 Engineers.
    • Repair SHIVs: Allows Arc Thrower to repair friendly S.H.I.V.s or captured Drones, 6 HPs repaired for each use. On the Enemy Within DLC it can also be used to repair MEC Troopers.
      • Requires: EMP Canon Research, 10 Engineers.
    • Stun, Drone Hack, and Repair SHIV have separate commands from each other, but the Arc Thrower only holds two charges total: So it's two total of any combination of Stun, Hack, or Repair.


  • You'll need to get the target down to low HP in order to have any chance of capture (the lower the better). This can be quite challenging itself given the random damage of weapons - a "lucky" damage roll could kill a target you're preparing to capture.
    • Pistols are good for whittling away a target's HP. They have a base crit chance of 0, so provided you're not flanking the target you should do reliably low damage.
    • Alternatively, grenades and rockets do a fixed, reliable amount of damage.
  • Given the close range, a Support class soldier with Sprinter is a fairly good candidate for packing the Arc Thrower.
    • The Support's Deep Pockets ability does not allow him/her to carry another Arc Thrower...
    • But in the Enemy Within DLC, the ability has been changed to allow for an extra use, for a total of 3 charges (Tactical Rigging still doesn't allow for a second Thrower to be carried, though).
  • Alternatively, an Assault class soldier with Lightning Reflexes is another good candidate for the Arc Thrower as they can avoid the first overwatch shot of the target.
  • To ensure you don't lose soldiers because of a failed stun attempt, try stunning the alien using at least two people in one turn or have another soldier with a clear line of sight that can take out the target if the attempt fails.
  • Note that the Arc Thrower does not affect Chryssalids, Zombies, Cyberdiscs, Sectopods, Seekers or Mechtoids, so you do not have to capture them to gain all the research topics. Also, EXALT soldiers would rather commit suicide than be captured alive!
  • Also note that the Arc Thrower cannot be used on civilians, nor on your own soldiers, including if they are Panicked and even if they are Mind Controlled by the aliens. If you want to avoid killing a Mind Controlled soldier you will just have to run away and take cover until the alien Mind Control wears off.
  • If you have a Sniper with the Disabling Shot skill, you can make the stun much safer on the approach, and should the stun attempt fail the enemy will be unable to return fire on their next turn.
  • Enemies, particularly lone ones, will tend to retreat continually when approached. Overwatching will usually keep them in place, since the AI is very reluctant to move when it knows it would provoke an overwatch shot.
  • Use of Suppression fire is a good way to keep an enemy immobile and limit its ability to shoot while your Arc Thrower soldier approaches. Note that suppressing a target disables its overwatch fire.
    • An Alloy S.H.I.V with S.H.I.V Suppression makes a particularly good support unit for a stunner, as it can suppress and give the stunner cover exactly where they need it for an optimal approach.
  • In vanilla Enemy Unknown, there is an AI glitch for aliens: if they see two or more in-cover soldiers, at least one is flanking them, and they see either one go into overwatch, their AI locks up and they'll skip their next action. This is an excellent method to close in for a stun.
    • This is fixed in Enemy Within: aliens and EXALT agents will most often move and risk overwatch fire rather than leave themselves exposed to flanking shots.
  • The weapons of aliens taken down with the Arc Thrower will not shatter into fragments. Instead, the weapon is recovered in working condition and will appear in the XCOM base inventory (although it still needs to be researched the before soldiers can use it).
  • Repair SHIV and Drone Hack have more range than the stun function.
  • For any applicable targets (alien, Drone (hacked or not), or S.H.I.V.) where any Arc Thrower action is available, a range of use is shown as a blue ring with lightning bolt symbols, centered on the target. There is some leeway in differences in altitude, but the distance range for if a soldier might not make it entirely in the circle, is if the dot at the end of a soldier's movement line (in the center of the square you'll be moving your soldier to) is within the circle. Be sure to change the camera angle, as the line is directly on the floor, while the circle hovers a few feet off the ground: perspective may not make it clear if a soldier will be in range in 1 move.
    • A soldier can usually stun at a maximum of 2 squares between him/her and the alien.
  • The Arc Thrower's chance of success is not a normal hit roll, so is not affected by wounds, high ground, Holo-Targeting or anything else that normally affects aim.
  • Stunning a mind-merging Sectoid does not kill or stun the mind-merged unit, the latter only loses its buff.

See Also

EU2012 Badge XCOM: Enemy Unknown (2012): Soldier Equipment
Light:Body Armor
Medium:Carapace ArmorSkeleton SuitGhost ArmorPsi Armor
Heavy:Titan ArmorArchangel Armor
MEC Suits:MEC-1 WardenMEC-2 SentinelMEC-3 Paladin
Conventional:PistolAssault RifleShotgunSniper RifleLMGRocket Launcher
Laser:Laser PistolLaser RifleScatter LaserLaser Sniper RifleHeavy Laser
Plasma:Plasma PistolLight Plasma RiflePlasma RifleAlloy CannonPlasma Sniper RifleHeavy PlasmaBlaster Launcher
EXALT Weapons:EXALT Assault RifleEXALT Sniper RifleEXALT LMGEXALT Rocket LauncherEXALT Laser RifleEXALT Laser Sniper RifleEXALT Heavy Laser
MEC Weapons:MinigunRailgunParticle Cannon
Items:EU: Alien GrenadeArc ThrowerChitin PlatingCombat StimsFrag GrenadeMedikitMind ShieldNano-Fiber VestS.C.O.P.E.
EW DLC: Flashbang GrenadeGas GrenadeGhost GrenadeMimic BeaconNeedle GrenadeReaper RoundsRespirator Implant

EU2012 Badge XCOM: Enemy Unknown (2012): Research
Initial:Xeno-BiologyAlien MaterialsWeapon FragmentsMeld Recombination (EW DLC)
Lasers:Beam WeaponsPrecision LasersHeavy Lasers
Plasma:Plasma PistolLight Plasma RiflePlasma RiflePlasma SniperHeavy PlasmaAlloy CannonGuided Fusion LauncherPlasma CannonEMP CannonFusion Lance
Armor:Carapace ArmorSkeleton SuitTitan ArmorArchangel ArmorGhost ArmorPsi Armor
Technology:Arc ThrowerExperimental WarfareEleriumUFO Power SourceAlien Nav ComputerNew Fighter Craft
Interrogations:Interrogate SectoidInterrogate FloaterInterrogate Thin ManInterrogate MutonInterrogate Sectoid CommanderInterrogate Heavy FloaterInterrogate BerserkerInterrogate Muton EliteInterrogate Ethereal
Autopsies:Sectoid AutopsyFloater AutopsyThin Man AutopsyMuton AutopsyChryssalid AutopsyDrone AutopsyCyberdisc AutopsySectoid Commander AutopsyHeavy Floater AutopsyBerserker AutopsyMuton Elite AutopsySectopod AutopsyEthereal AutopsySeeker Autopsy (EW DLC)Mechtoid Autopsy (EW DLC)
Other:Research CreditsResearch Codenames