Husk

Husks are synthetic 'zombies' created by the geth. When a human is captured they are placed on impaling devices, huge spikes that Alliance marines have nicknamed 'dragon's teeth'. Over time the body's organs, skin and water content are converted into cybernetic materials; blood is changed to a sickly green fluid, and the body generates an electrical charge.

When the spikes are approached - say, if marines try to recover their dead comrades - the Husks are released and attack. The Husks will charge at their enemies and, once close enough, give off a powerful electrical blast which disables shields and causes massive damage.

Husks are encountered throughout the game, first on Eden Prime and then anywhere humans have been fighting the geth. No one knows why the geth do this to their captives: it seems like a lot of effort for a small result, though it is effective psychological warfare to make soldiers fight their own dead. The geth used a ship full of Husks, the MSV Cornucopia, partly as a trap and partly as a warning to other organic races not to enter their space.

Cerberus were studying Husks as part of their experimental programme into creating a super soldier. They deliberately exposed a colonial pioneer team on Chasca to dragon's teeth, and had more Husks as test subjects on Binthu. There were also Husks in Saren Arterius' research facility on Virmire, likely part of his study into indoctrination.

When Sovereign 'possesses' Saren's body, the resulting creature strongly resembles a Husk, and the Reaper indoctrination effect is similar to the 'zombie' nature of Husks, which suggests that the dragon's teeth are Reaper technology; this is confirmed in Mass Effect 2. A cache of the spikes was found buried on Trebin and had to be excavated by the local research team, but there is no evidence of who put them there or why.

Tactics (Mass Effect)
While not as resistant to damage as Thorian Creepers, Husks are still quite resilient. If they get close enough on foot, their electrical blast carries over a large area. This damages the entire squad and overloads their shields, and if there is a large group of Husks this can be lethal. Husks are vulnerable to Warp and Neural Shock (although they appear robotic, they count as organic enemies as they are corpses, and AI Hacking does not work), and tech abilities like Damping or Sabotage can also slow them down. Otherwise, if they haven't used their electrical attack, it's safer to keep them at a distance and pick them off, using Throw if they get too close.

Like Thorian Creepers, the unarmored bodies of Husks are vulnerable to mêlée strikes. The Husk tends to pause for a brief period after using its electrical attack, allowing ample time to perform a mêlée attack. This tends to inflict light to moderate damage and is virtually guaranteed to knock the Husk down.

Mass Effect 2
Husks are now known to be of Reaper origin when it is clearly stated several times that the geth gained their dragon's teeth from the Reapers.

The Collectors appear to make use of Husks which are noted to be more advanced than those previously fought by Commander Shepard. It is also noted that no dragon's teeth are ever seen where the Collectors make use of Husks, though what this means is unknown. The Collectors also make use of several Husk variations: the Abomination, the Scion, and the Praetorian. A similarly advanced type of the standard Husk, as well as Abominations and Scions, is also found aboard a derelict Reaper when a science team falls victim to indoctrination and finds a supply of dragon's teeth onboard. Why the Husks previously encountered were less advanced and why no Husk variants were seen serving the geth, is unknown, though most likely Soverign was uncomfortable with giving the geth too much of its technology. These advanced Husks lack the ability to produce electrical blasts however. If you travel to the Minos Wasteland there is a side quest that deals with an excavation team on the plant Aequitas that found an alien artifact that creates husks. This device does not look like dragons teeth at all but instead is an orb filled with an unknown energy source that turned the excavation team into husks.

Tactics (Mass Effect 2)
Husks now attack by charging at Shepard or his team and attempting to maul them. Once they start rushing, they can be sidestepped easily causing them to helplessly dash past you. You can also stop them by shooting their legs out from under them, ideally using a Submachine Gun or an Assault Rifle. Armor Piercing Ammo is particularly effective. Concussive attacks, like Concussive Shot or Shockwave are very useful against them, as those can usually rip some of their body parts more easily than guns. Freezing a Husk completely will cause husks to burst (not confirmed on Insanity, but confirmed on Hardcore)


 * Abominations are standard Husks which glow red rather than blue and act as suicide troops. They appear to catch fire and then attempt to charge at a target. Regardless of how they are killed, they explode upon death. This can stumble or kill other Husks, which is quite useful in hectic situations. If they are killed before they glow, such as when they are spawning, they will not explode.
 * Scions are three Husks morphed together and grafted around a single hybrid mass effect/biotic weapon on the left arm. The 'sack' on their back contains redundant organs, systems and element zero sources to provide power for the weapon. Scions are essentially walking genetic experiments, crudely fusing Reaper technology with human anatomy. Scions are slow moving masses with a lot of armor. They also release shockwaves periodically during combat. The Handcannon pistol/sniper rifle + armor piercing/warp ammo is effective against their armor, as is repeated usage of Incinerate, Warp or Reave. Sniper rifles and heavy weapons are also adequate for taking them down quickly.
 * Praetorians are formidable flying creatures made of thirty Husks, deformed so much that they no longer resemble a human being. Clearly fusing Collector DNA with the combined nervous systems and organs of several human subjects (giving them incredible durability) these powerful flying suits of armor are another example of horrific Reaper experimentation. In combat, they attack using a powerful particle beam emitted from their eyes, or with melee attacks. Additionally, they can put up strong barriers around themselves multiple times, making them very tough. When putting up a barrier, they are temporarily immobilized and incapable of attacking, but they send out a shockwave that can seriously harm any squadmates who are too close.