It's a type of device that's implanted into a person's brain in adolescence if they show biotic potential. I suppose you could call biotics space magic. The implant is designed to amplify biotic power in humans so the biotics can be useful to us. The L2 models are notorious for allowing a person to be extremely powerful biotically, but it tends to cause people to go insane, or suffer intense, chronic pain. My implant is not an L2 model, it's much better quality, but right now I think it's malfunctioning and acting like an L2 model.