ADVENT Stun Lancer (XCOM2)
The Stun Lancer is a specialist ADVENT soldier wielding an electrically-charged baton/sword and a magnetic rifle. They are moderately durable with 4-8 health, difficulty dependent.
Stun Lancers are infamous for their total disregard for their own safety. They charge forward like XCOM's Rangers, except with a Shock Lance that deals 2-4 damage. Worse yet, the Shock Lance can inflict Disorientation, Stunned, or even Unconsciousness on their victim, with the latter effectively killing them for the duration of the mission. Should they miss, however, they are quite finished.
Although their AI makes them use their Shock Lance at any opportunity, they are also equipped with a regular Magnetic Rifle,which deals 3-4 damage.
Stun Lancers evolve into Heavy Lancers and Elite Lancers as time passes. Their later forms have increased stats and an armor point, but their arrivals typically coincide with the unlocking of Magnetic and Plasma weaponry, allowing them to be dealt with.
A decent counter is a Ranger with Blademaster, but early Stun Lancers come before the arrival of XCOM Captains. Frost Bombs from a Grenadier are quite effective in halting them, and Psi Operatives with Stasis can freeze them to be killed later. Their Will is generally low, allowing Psi Operatives to mind control them, and perhaps even knock other enemies unconscious. If all else fails or XCOM is training rookies, massed Overwatch fire will almost certainly kill them.
Remember, however, that a strong offense is the best defence, and a grenade to their cover followed by a shot will put them down as easily as any other ADVENT trooper.
The autopsy reveals that the Stun Lancers are extremely high on combat stims, which contorts the faces into hideous grins after death. Since they are more durable than normal Troopers, the implications are such that the aliens bear some "genetic frugality" about them. The Arc Blade, the Tier 2 sword, is unlocked after the autopsy is completed.