What is happening with Tybalt how is he described by Mercutio?

Act 2 Scene 4 – What is happening with Tybalt? How is he described by Mercutio? Tybalt has sent a letter to Romeo’s father. Mercutio says he is a great, courageous man.

What did Mercutio call Tybalt?

Prince of Cats

Mercutio repeatedly calls Tybalt “Prince of Cats” referring to Tybalt’s expertise with the sword, as he is agile and fast, but also it is an insult.