The Syringe is a weapon used by Valoopy, a highly skilled medic and decent sniper of the NCR. He uses it to cure people of a particular disease. The name of the aforementioned disease is "Being a Legionary". To cure an infected individual, simply aim at the head of the legio-err, infected, and pull the trigger. The bullet should penetrate their skull and blast it clean off their shoulders, curing them of this most atrocious of diseases.