This is an example of "expressive crowds".
Expressive crowds refers to a gathering of individuals who assemble to express feelings or feel fervor as chance to participate. As its name suggests, an acting group goes one vital advance past an expressive swarm by carrying on in savage or other dangerous conduct, for example, plundering. A horde—a seriously enthusiastic group that submits or is prepared to confer brutality—is an essential case of an acting group.