Mass Effect Wiki
Mass Effect Wiki

Swarmers are synthetic-organic creatures presumably derived from Rachni Workers and mutated by Reaper technology. Swarmers can be spawned by puncturing one of the large orange sacs found on Ravagers or by destroying Gestation Pods.



Swarmers are volatile in large groups and can hinder shield regeneration with constant attacks. Namely, Swarmers attack by a suicide leap at the player, damaging with both the explosion and a little bit of acid damage-over-time.


Swarmers are very weak with only a small amount of health and can be killed by one shot from any weapon, a melee hit, or one attack from any power that deals direct damage. They also have a limited life span and eventually die spontaneously. Despite having no special protections, Swarmers appear to be entirely unaffected by Cryo Blast or other non-damaging freezing powers as they do not slow down or become chilled or frozen.


  • Slow-moving and fragile, these small targets are easy to miss. Since Swarmers tend to appear in groups, attacks with an area of effect are generally effective in dealing with them.
    • Explosive projectile weapons like the M-37 Falcon assault rifle, Scorpion pistol, and Krysae Sniper Rifle sniper rifle may take out multiple Swarmers at once.
    • Powers like Singularity, Chain Overload, a Stasis bubble, or any kind of grenades are also reliable ways of dealing with groups of Swarmers.
    • Since Annihilation Field does damage automatically and auto-targets once the foe is in range, it can be a very effective deterrent towards Swarmers.
    • Dark Channel is very effective against Swarmers as it will kill Swarmers instantaneously if it travels to one and then will rapidly jump to other nearby Swarmers until they are all killed.
    • It doesn't show on the kill log but Reave instantly kills all Swarmers in its area of effect.
    • Although wholly a defensive power, activating Shield Boost will destroy Swarmers within its radius (without displaying a kill notification).
    • At the moment it is cast, the Biotic Sphere does a small amount of damage to enemies inside or touching it, killing Swarmers outright.
    • If used against Swarmers, Tactical Scan will kill them instead of causing its normal effects.
    • Swarmers are drawn to Sentry Turrets, Combat Drones, and Decoys but can't attack them, making all three of these powers useful "bug zappers" especially when evolved with attacks that can hit multiple nearby enemies.
  • One very important thing to keep in mind when facing lots of Swarmers, especially for power-centric classes, is that most non-grenade powers in Mass Effect 3 have a maximum number of targets they can hit, even when the power has an area of effect, usually capped at 3 or less. Power Combos are capped at hitting a maximum of 4 targets. This makes mass Swarmers obnoxiously good at absorbing player powers and preventing them from hitting more threatening enemies in the area.
    • The detonation of Tech Armor can hit any number of targets within its blast radius and is an effective anti-Swarmer measure. The detonation of Barrier is capped at 3 targets hit.
    • This can also apply to certain heavy melee attacks that can hit a maximum number of enemies such as the krogan charge in multiplayer. Especially when attempting melee attacks against Ravagers, the Swarmers they summon can interfere with and block melee attacks from landing on them.
    • Grenades on the other hand are not limited in the number of targets they affect within their detonation area, making them both very handy for clearing out Swarmers, and making regular powers that much more effective as well.
  • Being a "summoned" unit, Swarmer kills don't count as enemy kills in certain situations.
    • Eliminating all active Swarmers is not required to complete a current multiplayer wave. Because of this you should always stay vigilant as a pack of Swarmers can quickly eat away at your health or any health recovered, even after the wave is completed.
    • Swarmers do not count as enemies killed towards activating Rage for krogan classes or Bloodlust for vorcha classes in multiplayer.
    • Killing Swarmers with heavy melee attacks does appear to grant the on-kill bonuses of the Rank 5 and Rank 6 melee damage-centric evolutions of the other various Fitness-type powers.
    • In single-player, the existence of Swarmers will prevent squadmates from reviving even if all other enemies in the area have been eliminated.
  • If the Swarmer dies from contact with a player character, whether by leaping or being stepped on, it leaves a puddle of acid that deals damage over time.
  • If the player kills the Swarmer first, even with a melee attack, the player will take no damage and no puddle of acid will remain.
    • Melee attacks work best while hosting in multiplayer since latency can prevent a kill from being registered on time before a Swarmer bursts.
    • The melee attacks of certain multiplayer classes have a very hard time connecting with Swarmers, such as the regular or heavy melees of the N7 Slayer Vanguard, or the heavy melees of the Cabal Vanguard and all vorcha classes.
  • Sabotage works normally on the targeted Swarmer, which will be instantly killed by the delayed Backfire effect.
  • In multiplayer, if the player is killed by Swarmer acid, no kill notification is logged.


  • Swarmers' arachnoid, multi-legged bodies, acidic body fluids, and habit of leaping at targets after emerging explosively from "eggs" all bear strong parallels with the "facehuggers" from the Alien film franchise.