Tracer

The Tracer is the secondary purification weapon in Child of Eden. It can be used on any virus, but is the only way to weaken purple viruses. It can also shoot down purple projectiles. It is twice as weaker than the Lock-On Laser.

Xbox
With the Xbox controller, you can use the Tracer by holding X or Right Trigger (control type A). On Kinect, you can use the Tracer with your left hand (gesture type A).