Oculus

The Oculus is a fast-moving device used by the Reapers as a space and atmospheric superiority craft. They were first seen being used by the Collectors to protect the Collector Base.

Oculi are cybernetic constructs, being piloted (in the case of those used by the Collectors) by a single Collector drone. Each drone is stripped down until only its nervous system remains, with the remaining tissue hardened to withstand vacuum and integration into an Oculus shell.

Oculi possess powerful beam weapons, similar to other Reaper and Collector weaponry, and can invade an enemy ship by cutting into its hull after jettisoning part of its armor.

Mass Effect 2

Oculus
Type	Synthetic
Faction	Collectors
Armament	Particle Beam Weapon
Abilities	None
Armor	Very High
Locations	Tartarus Debris Field

The Normandy SR-2 is attacked by several Oculi when attempting to reach the Collector Base. The Oculi were apparently left on guard in the local debris field and only activated as the Normandy approached. While most of the Oculi are destroyed by the Normandy's weapons or by accidentally flying into debris, one is able to penetrate the ship's hangar deck, losing its outer shell in the process. It is eventually destroyed by Commander Shepard.

It is likely that the Collectors gained the Oculus technology from the Reapers.

The Oculus' particle beam is strong enough to slice through a hull without Heavy Ship Armor, and can potentially kill Jack if the Normandy lacks the upgrade.

Capabilities

Offensive

The Oculus' beam weapon is much stronger than an ordinary particle beam, and will blast away any shields or barriers in a moment, especially on higher difficulties. It fires its weapon in very long bursts, thus anything longer than a brief exposure to this weapon could be fatal.

Defensive

The Oculus has an incredibly strong armor, which acts as its health.

Tactics

• Shooting the red "eye" causes more damage than shooting the silver shell.
• Standard weapons with high armor damage bonuses (such as the M-98 Widow, M-92 Mantis, M-5 Phalanx or M-6 Carnifex) are effective, if a little time consuming and dangerous. Your squad will continually comment that it will take heavy weapons to succeed, but it can be done with pistols if that's the way you want to go.
• Explosive heavy weapons (such as the ML-77 Missile Launcher or M-100 Grenade Launcher) are quite effective. However, using M-920 Cain is not recommended as its explosion can easily kill you. The Collector Particle Beam and M-451 Firestorm are effective as well, but you are highly exposed to the Oculus' own particle beam, which is not recommended on higher difficulties.
• Powers such as Incinerate, Warp, Reave and/or Incendiary Ammo are very good in stripping away its armor. Most biotic powers (except for Warp and Reave) are ineffective.
• The three "shield" powers (Geth Shield Boost, Fortification, and Barrier) are immensely helpful in protecting yourself while fighting the Oculus. Wait until the Oculus is just about to clear your cover, activate the power, and sprint to the other side of the room. If timed correctly, the extra shielding from a maxed-out boost can protect you out in the open all the way to the other side, and the power will be available to you the next time the Oculus reaches your position.
• The Oculus is unaffected by Stasis.
• The Oculus can see through Tactical Cloak.

Mass Effect 3

Oculi are deployed en masse by the Reapers during their 2186 invasion, serving as atmospheric and exoatmospheric fighters and interceptors. Several Oculi can be seen during the initial attack on Earth, attacking Alliance fighters and A-61 Mantis Gunships. Squadrons are also seen in action over Palaven and later during the battle to retake Earth.

No Oculus directly engaged Shepard during the war, in contrast to the Normandy incursion earlier.

Trivia

• Oculus is Latin for 'eye'.
• The center of a Destroyer's primary beam weapon is identical to an Oculus.
• The Oculus' design was based on a stereo speaker, and the reference for the eye was HAL 9000.