Scion

The Scion is a type of Husk which appears in Mass Effect 2. It is made from three Husks fused together and grafted around a single mass effect/biotic weapon on the left arm. The blue 'sacks' on their backs contain redundant organs and element zero sources to provide power for their weapons and shockwaves. Scions operate well alone or in pairs, hanging back as several Husks and occasional Abominations rush ahead. Less mobile, Scions provide fire support, lumbering behind the wave of attackers while firing weapons and discharging biotic attacks.

Capabilities
Offensive

The Scion is armed with Shockwave, but unlike the class power, the Scion's version is much more powerful and can deplete Shepard's shields with one hit, penetrate thin cover and knock back enemies, even on the lower difficulties. This powerful blast also travels a long distance. Scions carry a weapon similar to an assault rifle grafted to their arm, but this weapon is only used at close range. Scions can also create a blast wave at close range which can deplete shields in one hit. If a character is hit with a Shockwave, then it will take noticeably longer for their shields to recharge, though this can be countered with powers like Geth Shield Boost, Tech Armor or Unity, provided Emergency Shielding has been researched.

Defensive

The Scion is very heavily armored, but does not possess any barriers or shields. The armor also serves as its "health".

Tactics
General Notes Class Specific Notes
 * The head of the Scion is located on its right 'shoulder' and is a confirmed weak spot.
 * In terms of weapons, any player class that has a sniper rifle will have the advantage in a fight against a Scion. This allows you to keep the fight at a distance and have room to dodge its attacks. Paired with Armor Piercing Ammo or Incendiary Ammo, this would be the best combo against it. If the sniper rifle is not available, the Collector Particle Beam is an efficient alternative.
 * There is also a second possible weak spot at the rear of the Scion in the form of a bright blue circle; however this requires a distraction to expose, for example a Combat Drone. Note that given the devastating nature of the Scion's weapon and the size of the areas they appear in, it is dangerous to attempt such a tactic without absolute clarity on your approach.
 * Another weak spot: the membranous hump on the Scion's back. Sniper fire can burst the bubble, killing the Scion in just a few shots (two with the M-98 Widow on lower difficulties).
 * In some fights, the Scions remain stationary and inactive if you keep your distance (the distance that doesn't trigger the HUD to display its health). In this scenario you can save a lot of pain by shooting it from afar. Chances are you can eliminate the unit without it engaging you.
 * If Shepard chooses Stasis as his/her bonus talent, he/she can use it to disable the Scion and take out the husks easily, without having to worry about the Scion's devastating attacks. If the Scion is on the edge of an area, Shepard can also use Stasis on the Scion, and when it comes out it may fall off the ledge and die.
 * Players can use defensive powers like Barrier, Fortification, Geth Shield Boost, or even Unity with the proper upgrades to counteract the Scion's ability to delay shield regeneration.
 * Flashbang grenade is a useful means of disabling the Scion's main attack.
 * An Adept's Singularity can keep a Scion rooted in place and unable to attack for a short time.
 * Vanguards can use Charge to quickly close with a Scion, bypassing its deadly long range attack. Once in close combat, players can backpedal away from the Scion, ideally moving far enough to avoid its close combat burst attack.  This strategy can be repeated again and again, triggering the Scion's close combat attack only to move out of range before it fires.

Trivia

 * In horticulture, the term 'scion' refers to a method of grafting plant tissues together.