What do the plebeians do in Act III, scene 3 of Julius Caesar?

Having shown how Antony unleashed the power of the mob in
Act III, scene 2, Shakespeare in this scene shows us the true nature of the power of the
plebeians in Rome, and how, with the vacuum that the conspirators have created through
killing Caesar, chaos and anarchy have descended upon Rome. The plebeians meet a poet
who bears the same name as one of the conspirators. Even though he protests his
innocence and is clearly not a conspirator, the plebeians nevertheless take him away to
be beaten to death. Note the picture of chilling violence with which this scene
ends:

Tear
him, tear him! Come, brands, ho! Firebrands! To Brutus', to Cassius'! Burn all! Some to
Decius' house and some to Casa's; some to Ligarius'! Away,
go!

Violence and murder rule
the streets of Rome, and we see that Antony has taken a gamble in unleashing such
irrational violence and cruelty that runs amuk.

In a sense,
of course, we find this scene parallelling the assassination of Caesar. Just as Cinna
here is the wrong man that the mob are looking for, so, in a sense, Brutus and Cassius
were mistaken in their assumption that killing Caesar would end his power and rule.
Although they have killed the physical Caesar, they underestimated the power of the
symbol that he had become, which Antony is able to use so well to make the mob rise
against them. They, too, killed the wrong man in a symbolic
sense.