Sarin is a highly toxic nerve agent that was originally developed in Germany in 1938 as a pesticide. It disrupts the normal functioning of the nervous system by inhibiting the enzyme acetylcholinesterase, leading to an accumulation of the neurotransmitter acetylcholine. This can result in severe symptoms, including muscle spasms, respiratory failure, and potentially death. Due to its extreme toxicity, sarin is classified as a chemical weapon and is banned under the Chemical Weapons Convention. It has been used in several terrorist attacks, most notably the 1995 Tokyo subway attack, highlighting the dangers associated with chemical warfare and the importance of global disarmament efforts.