As the climactic scene of the play, Scene 1 of Act III opens with literary techniques:
The first public place was the site of much acrimony; this location on a day that is hot portends danger as words such as "hot," "brawl," and "mad blood" are used.
Mercutio compares Benvolio to a sman ready to fight by the second drink using a simile:
Thou artlikeone of those fellows that when he enters the confines of a tavern claps me his sword upon the table and ...by the operation of the second cup draws him on the drawer, when indeed there is no need.
Mercutio counters with a simile himself (first bold phrase) as well as using alliteration with the /m/. And, the phrase in which "as soon moved to be moody" is balanced against the following phrase that is inversed, "as soon moody to be moved," is a rhetorical device called chiasmus.
Come, come, thou art as hot a Jack in thy mood as any in Italy, and as soon moved to be moody, and as soon moody to be moved.
This device is also used in Mercutio's longer speech beginning with "Nay...."
Then, there is another simile: "Thy head is as full of quarrels as an egg is full of meat"
It is ironic that Mercutio scolds Benvolio for his anger when he will soon explode into invective against Tybalt.
Of course, Mercutio banters words with Tybalt excercising wordplay, taunting him with seemingly playful remarks:
TYBALT: You shall find me apt enough to that, sir, an you will give me occasion.
MERCUTIO: Could you not take some occasion without giving?
Mercutio plays on the double-meaning of "consort" in his retort to Tybalt
TYBALT: Mercutio, thou consor'st with Romeo,--
MERCUTIO: Consort! what, doest thou make us minstrels? an
thou make minstrels of us, look to hear nothing but
but discords: here's that shall make you dance. 'Zounds, consort!
Another pun that Mercutio uses is on the word "grave." When he tells Romeo :ask for me tomorrow, and you shall find me a grave man," he means both no longer joking, but "serious" and also "dead."
Mercutio affords submitting to Tybalt's insults the qualities attributed to people: "O calm, dishonourable, vile submission!"
Mercutio makes reference to "King of Cats," a sobrique that he has given Tybalt. when he calls Tybalt a "rat catcher."
After the enraged Romeo kills Tybalt, he calls himself "fortune's fool," a metaphor (comparison in which one thing/person is equated for another quality, person, thing) for his being a victim of fate.