A person that has had a previous history of uncontrolled outbursts of anger. They may scream, yell, and even become physical due to small and insignificant occurances.
Did you see how mad he got after missing that shot? What a snapshow.
or
All I did was make a simple joke, yet the snapshow had to take it seriously and punch me.
When a person (usually a young female) becomes emotionally unstable and maniacally loses their temper on a regular basis, most often when debating on topics such as driving skills, hygiene and the glass ceiling.
A person who gets extremely angery (snaps) and makes a large scene. Generally, a person is labelled a snap show only if they are unnecessarily angry over something completely unimportant.