Banshees – Mass Effect 3
Created by Reapers from corrupted Asari, banshees show up a good way into Mass Effect 3. And they can go straight back to where they came from as far as we’re concerned: They’ll charge your team, can teleport around, and can fire heat-seeking warp projectiles. Add to that the fact that they can blast your fire team out of cover and can soak up a ton of damage, and you’ve got the most annoying enemy type in Mass Effect.
Plus there’s that horrible, awful scream.