The protesters at the Egypt uprising rally were an acting crowd. Egypt started to protest against the stifling rule of longtime President Hosni Mubarak. Then, flash mobs appeared. Flash mobs are a large group of people who gather together in spontaneous activity and are examples of collective behavior. The crowd is one of the forms of collective behavior. There are four types of crowds: casual, conventional, expressive and acting. Acting crowds focus on a specific goal or action, such as a protest movement or riot.