Using an infusion of human DNA, the Sectoid has grown into a much more imposing form than when it was first encountered. They are significantly taller than their Enemy Unknown versions, and now have a visible mouth with teeth. They are still fairly thin though, and their chest still glows. Sectoids use wrist-mounted blasters that are similar to the Plasma Pistols of the original Sectoids, but smaller and seemingly designed for use on the arm instead of merely mounted there. The blasters are handled by the Sectoids in a similar fashion to the original Sectoid Commanders, using them as "last-resort" weaponry when psionic chances are too low or impossible. When first spotting XCOM personnel Sectoids will commonly raise the blaster to their mouth and appear to "speak" into it for a few moments before resuming engagement, suggesting that the device may assume a communications role as well. Sectoids have a medium amount of HP, but no armor.
- Mindspin: A "roulette-wheel" type attack with a variety of different effects, potentially including mind-control.
- Psi-Reanimate: Summons a Psi Zombie from the corpse of a humanoid target. The Psi Zombie is able to move around independently, but will die if the Sectoid is killed or afflicted with a turn-denying effect.
- Takes +3 damage from melee weapons, effectively doubling Tier 1 sword damage, thus making them ideal targets for Rangers and Templars.
- Flashbangs and other disorienting effects will cause psi-controlled characters to become disconnected from the Sectoid - this also causes Psi-Zombies to instantly die.
- In the early game, Sectoids are always deployed as pod leaders followed by ADVENT. Later they will appear in pods made entirely of Sectoids or as support troops for Gatekeepers. This change starts in May (June on Legend difficulty), but both types coexist for roughly one month.
- The Sectoid's ability to panic and/or mind control soldiers is extremely dangerous in the early game when squad sizes are smaller and soldiers haven't gained enough Will to effectively resist Mindspin. As such, these units should be put down as rapidly as possible, especially on Legend.
- It is a good idea to equip a Grenadier with a Mindshield and Flashbang Grenade specifically to combat Sectoids. Their immunity to panic and mind control, along with the ability to Disorient Sectoids in order to break panic and mind control for allies along with killing psi-zombies is invaluable early on in the game.
- Like several other creatures of XCOM 2, the new design of the Sectoid is a throwback to the classic X-COM: UFO Defense. The most evident characteristics are the more humanoid posture, greater resemblance to the classic "grey aliens" and addition of facial features. The Sectoid also incorporates certain parts of the Enemy Unknown design, such as the glowing chest and wrist-mounted weapon.
- If a mind-controlled Sectoid revives a corpse, the resulting zombie will stay alive and be friendly even if the Sectoid escapes mind-control or dies. Zombies count as actual soldiers (missions involving mandatory evac cannot be finished until friendly zombies are killed as they cannot be evacuated) and their deaths reduce the score of missions.
- In the War of the Chosen expansion, the Psi strength of Sectoids is reduced to 40 on Rookie difficulty only. On Veteran+, Psi strength is 90, which virtually guarantees a successful psionic attack when without a Mindshield due to how Will has been reworked, even on Colonel ranked soldiers. This may be a developing oversight.