Answer

We have been told that there are three states of matter, but this is not true. There are many other states also present. One of these states is plasma which is formed when we superheat gases. So formally we could define plasma as a superheated gas. But it must be kept in mind that plasma shares no similarity with gases.Just like when a liquid changes to a gas and we no longer call it a liquid nor do we associate the same properties with it the same is applicable to plasma and gases. As to what matter exists in the plasma state: the best example would be the sun.