A nerve agent is a type of chemical weapon that targets the nervous system, specifically the neurotransmitter acetylcholine. These agents were originally developed for military use as they can cause rapid death through overstimulation of the victim's nervous system. The most well-known nerve agent is sarin gas, which was used in a deadly attack in Tokyo in 1995. Nerve agents are highly toxic and can be delivered through various means such as aerosol sprays or contaminated food.