Mass Effect Wiki
Mass Effect Wiki

The Geth Colossus is the largest geth ground unit.

Mass Effect[]

Geth Colossi are similar to Geth Armatures, but much larger with more health, stronger armor and better weaponry. They are distinctive from Armatures because their armor is brighter, somewhat platinum-silver in appearance, with ridges on the back. They are equipped with mass accelerator machine guns and a powerful Siege Pulse mass accelerator cannon. The Colossus is a monumentally dangerous foe, but fortunately they are almost always encountered while in the M35 Mako.


  • Like Armatures, Colossi will bring their legs together before firing the Siege Pulse cannon, giving you a small grace period to react accordingly.
  • The Colossus doesn't actually need to be facing your direction to fire, meaning you can still be hit by the Siege Pulse even if you're behind it.
  • Efficiently fighting the Colossus almost always means whittling it down with the Mako's guns. You'll only need to step out of the vehicle to deal the killing blow on foot if experience penalty is an issue.
    • So long as you stay at long range or circle-strafe using the main cannon, four or five shots will bring a Colossus down once its shields are gone.
    • For sniper-range distance engagements, you can simply park the Mako in a safe place (behind a wall or on the other side of a hill from the Colossus) once you have gotten the Colossus down to about 1/6th health or so, and send your squad members to the same hidden/protected area using the squad commands. Equip Shepard's sniper rifle and fire away. If you have done this correctly and your sniper rifle is reasonably strong, it should go down in a few shots.
    • If it becomes necessary to engage a Colossus at close range, repeatedly ramming it with the Mako to prevent it from entering the Siege Pulse firing position can prevent it from doing anything else while it's attempting to recover. This should typically be done if there are few enemies left (or only the Colossus itself), so you can bring your full attention to keeping it down while unloading mass accelerator fire on it.
  • It is possible to engage a Colossus on foot from start to finish with a well-equipped and balanced team, but your talents and weapons must be high level to pull it off. First of all, you must keep your shields charged with Shield Boost or Barrier or the Colossus' machine guns will shred them and kill you. Switch to Tungsten Ammunition and use either an assault rifle or shotgun to attack.
    • If you are out in the open, keep moving and spread your team out if you can. Cover is a bonus, but while Armatures will usually just stand there and fire in your direction if you leave their line of sight, a Colossus will actually give chase once you begin your attack, so bear that in mind if you have to fall back. Given the slow speed of a Colossus, unless trapped, running away, firing at it the whole time while dodging the Siege Pulse attack, will work.
    • The Colossus is too powerful for AI Hacking, Throw, or Singularity. Use them on lesser enemies.
    • Warp, Lift, and/or Sabotage all produce significant effects on the Colossus. However, you'll need Master Lift to get it off the ground as it's too heavy.
    • A Colossus has a very slow health regeneration at higher difficulties or levels, so toxic ammunition can be useful in hampering this. Its shield regeneration can occur quickly if left alone, so keep pressure on the walker before it erases your progress.

Mass Effect 2[]

There is one Colossus present on Haestrom, which acts as a level boss at the end of the mission to recruit Tali'Zorah vas Neema. A notable trait of this particular Colossus is that it is the Armature steel-gray, not white. Interestingly, the quarian marine Kal'Reegar calls the Colossus an "Armature-class" unit, indicating that at least quarians see it as a variation of the Armature.

There are also multiple Colossi on the Firewalker Pack, but they are fought with the Hammerhead and lack the self-repair mechanism, making them much less challenging.



The Colossus possesses a long-range siege pulse weapon and short-range mass accelerator machine guns. It should also be noted that the shots from the Colossus's main gun home in on whatever it is aiming at. This can make the fight very difficult. However, unlike in the original Mass Effect, this siege pulse will not kill in one hit, even on Insanity.


The Haestrom Colossus has very strong shielding and armor and will recharge its shields. It is unaffected by Stasis and can continue to target Shepard even while under the effects of Tactical Cloak. It will also ignore any allied geth under the effects of AI Hacking, remaining focused on Shepard's team.


  • The Colossus is protected with heavy shielding and armor. After destroying its shields, unload with heavy weapons and armor-damaging powers such as Incinerate or Warp. Once enough damage is done to its armor, it will collapse into a defensive position, enter into a self-repair mode and rapidly regenerate its shields. Damage done to armor is not repaired. When it enters its repair mode, wait until it stands back up before opening fire again.
  • A good way to defeat the Colossus is to bring its shield down to half, then use the M-920 Cain to destroy it from across the field. On lower difficulties, it is not even necessary to bring down its shield to destroy it with the Cain.
  • The Arc Projector can overload the Colossus' shields and armor with a few shots, making it easier to bring down.
  • If you don't have the M-920 Cain, just make your way up the right side all the way to the area right on the side of the Colossus and chip away at the shields with Overload. Once you are at this spot the Colossus won't self-repair. Once you make it down to the armor just use whatever heavy weapon you have to take it down. The M-98 Widow and M-96 Mattock work fine as well, more so on lower difficulties. Alternatively, keep chipping away at it with Incinerate or Warp.
  • Vanguards can try to immediately Charge at the Colossus, this should cause it to stop using its machine guns and rely only on the pulse cannon, giving players the chance to easily dispatch the Colossus. Using an SMG and squad powers to disable its shields are a good idea, followed by a salvo of shotgun shells with Incendiary/Inferno ammo. Players will have to constantly Charge at the Colossus, since other Geth will keep taking Shepard's shields down.
  • Positioning teammates correctly can split incoming fire between them and Shepard, an ideal idea would be to have a sniper wielding teammate far enough that they can dodge the Colossus and other geth assaults, and chip away at the shielding and armor of the Colossus. This is only possible from certain angles, and may be troublesome if the squadmates or Shepard become overwhelmed.
  • When piloting the M-44 Hammerhead, players can directly ram the Colossus, causing it to topple. This allows about three or four free hits. This can be done numerous times in succession.