When the comedian Jeff Ross started flinging insults at the Friars Club in the mid-1990s, the comedy roast was mostly seen as a relic. “It was like jousting or some lost art,” he said, recalling that comics poked fun at him for participating. “It was corny.”

Two decades later, what was once nostalgic has become cool again. The roast battle, which pits comics against each other in gladiatorial combat, has become the hottest new form in comedy today, with dozens of shows across the country and abroad. This week, it’s the focus of a four-part special on Comedy Central called “Jeff Ross Presents Roast Battle.”

At a time when rap battles have become popular online and onstage, the roast battle uses a similar format to update the ancient art of dueling put-downs. It probably began in Los Angeles in 2013, when a dispute between two comics was settled onstage at the Comedy Store in three one-minute rounds of insults after midnight. The organizers (the comics Brian Moses and Rell Battle) brought it back the next week, and buzz quickly built, turning the roast battle format from a cult hit among stand-ups to a frequently sold-out affair.

When Mr. Ross, who had become known as the Roastmaster General because of his performances on Comedy Central’s celebrity events, attended his first battle, he became rapidly convinced that the form was the next wave of roasting. The early Comedy Store shows, however, were too raw for television.