Chlorine Gas (also simply known as chlorine) is a very horrible chemical weapon used by the axis powers during World War 1. It is known for simulating the effects of drowning, without even being in liquid.
It is used in swimming pools in amounts that may cause coughing when swallowed, but it is NEVER enough to kill, unless more is added.
The gas appears to be a pale green-yellow gas, making it instantly recognisable from many other gases. It is also notably different because of the agony the victim will go through. It takes roughly 1 - 2 minutes for a victim to die from inhaling too much of this gas, causing a long, painful death if the victim inhales a lethal dose.
It attacks the respiratory system, mainly the lungs, by gathering at the bottom of them as it is heavier than air. In a few short breaths, vomiting and coughing will occur in about 30 - 60 seconds, with a few normal breaths, the lungs will be damaged, and taking just a few deep breaths can be fatal. It also irritates the eyes, making it even worse, as the victim may be caught off guard by this and panic, causing them to breath deeper which will ultimately kill them.
It is an illegal weapon due to it's horrific nature, and notably one that Scottyvich Baloneykov used that brought on many charges against him in 2006.