Human-Reaper

The Human-Reaper was an incomplete Reaper being constructed by the Collectors. Under the orders of Harbinger, the Collectors began abducting humans from colonies across the edge of the Terminus Systems, taking them to the Collector base.

Once at the base, the abductees were stored in organic pods. Periodically, they would be broken down into raw genetic material which was pumped through tubes to the centre of the Collector base and used to construct the Human-Reaper. EDI suggested that the Collectors were 'facilitating Reaper reproduction' by constructing a new Reaper, and also estimated that the Collectors would have to gather millions of humans in order to complete it. EDI also speculated that any Reaper is built to resemble the race used to create it, and that the Reapers had unsuccessfully attempted to construct a Reaper from Prothean raw material.

When Commander Shepard discovered the Human-Reaper, it was an inactive larva, supported by four tubes. These tubes funneled genetic material into the Reaper and also served as supports. After Shepard's squad destroyed all four tubes, the Human-Reaper fell into a pit to its apparent destruction. However, it was able to activate itself and climb back up to engage Shepard and the team. They proceeded to destroy the Human-Reaper once and for all by damaging specific points on its armour.

Capabilities
Offensive

The Human-Reaper slams the battlefield with its limbs, occasionally tearing away a platform. If standing near the edge when this occurs, Shepard may be knocked off the platform and killed. The Human-Reaper also possesses a ranged-energy weapon fired out of its mouth. This weapon requires a charge-up time, signified by distinct visual and sound cues, and will damage any Collectors in its path.

Defensive

The Human-Reaper cannot be destroyed through conventional means. It possesses a number of 'Weak Spots' in its armor that must be attacked in order to defeat the Human-Reap

Tactics

 * Before the actual fight with the Human-Reaper, if the player takes too long to destroy a tube when the covers open, the Human-Reaper will attack using its head-mounted weapon, despite being apparently inactive.
 * At least on normal mode, the fight against the Human-Reaper is fairly simple. Keep to cover when it is out. The Infiltrator's and Engineer's Incinerate power or a biotic's Warp are particularly effective when fully leveled, as are sniper rifles and the Reave bonus power. However, it is not easy to hit it with powers when Human-Reaper quickly changes its position, so it would be wise to wait until Human-Reaper stops for its charge-up attack. While other heavy weapons are effective, the constant exposure from the Collector Particle Beam deals significant amount of damage. As long as you keep to the center of platforms and in full 180 degree cover from it, there is a high chance of winning with little difficulty.
 * The M-920 Cain is capable of taking a huge chunk out of the Human-Reaper's armor bar, although this is difficult and is at best a gamble. The charging time on the weapon means that you'll be exposed to any incoming fire, and the fact that the Human-Reaper moves around further adds to the difficulty. If brought, it is best used early in the fight when the Human-Reaper is moving around a lot less.
 * No matter the difficulty, even on Insanity, being a Soldier with a Widow Anti-Material Rifle applied with Incendiary Ammo, Armor Piercing Ammo, or Warp Ammo and using Adrenaline Rush will help you focus on some decently placed powerful shots that will cut down the Human-Reaper's health drastically. Depending on your playthrough, this might cause it to start moving around sporadically and stop Collectors from showing up till you cease firing.
 * On Insanity, using Tali and Legion for this fight can be extremely helpful, provided both have full points allocated for their drones. Their drones will distract the Collectors and Harbinger so you can focus on the Human-Reaper itself.
 * When the Human-Reaper fires its weapon at you, it can and will kill any Collectors and even Harbinger that get caught in its line of fire. Careful positioning of yourself and your squad can lead to the Reaper wiping out entire waves of drones.
 * If the Human-Reaper's attack hits Shepard or any member of the squad, it will prevent their barriers/shields from recharging for a period of time. This is indicated by red bolts of lightning coursing over the character(s) in question. This can be countered by throwing up Fortification, Geth Shield Boost or Barrier.

Killing Harbinger when he appears causes him to drop power cells that refill ammo for all of Shepard's weapons, including heavy weapons.

Trivia

 * During development, the Human-Reaper was nicknamed "Baby."
 * The Human-Reaper as seen in-game was meant to be the core of a larger Reaper more reminiscent of Sovereign, Harbinger, and the other Reapers seen thus far.