I wonder where Avenatti learned to play the dozens

[The Velveteen Ocelot]

10. Interestingly, insult contests in poetry seem to have existed

in a variety of cultures for centuries - for example, Norse, old English, Celtic, Inuit, Arabic, ancient Greek, Japanese and Finnish. https://en.wikipedia.org/wiki/Flyting "The exchanges would become extremely provocative, often involving accusations of cowardice or sexual perversion."... "Flyting is similar in both form and function to the modern practice of freestyle battles between rappers and the historic practice of the Dozens, a verbal-combat game representing a synthesis of flyting and its Early Modern English descendants with comparable African verbal-combat games such as Ikocha Nkocha."

Maybe it developed independently in various societies as a ritualized way of fighting without violence. Now it's becoming a Twitter form!