Conor McGregor labelled Nate Diaz "a skinny little fool" as the bitter rivals fuelled speculation over a third fight.
McGregor is currently out injured with a broken leg after suffering his third defeat in four fights against Dustin Poirier at UFC 264 this summer.
The Irish star is pondering a return to the cage after his rehabilitation and has called out current welterweight champion Kamaru Usman among others.
But he has now re-ignited his feud with Diaz after tweeting a picture of their face-off with the caption: "Add 30lbs of muscle on me and say ding dong in an Irish accent."
Diaz responded: "Bro u can’t walk or fight right now why u talking s***? We talk later."
The Irishman then launched his latest assault, retorting: "Who can’t? Come through and see you little skinny fool, you will be smacked up and rolled up you bum. Cali's mine."
Diaz won the first meeting between the pair with a second-round submission in 2016 before McGregor avenged his defeat later in the year with a historic decision victory in a brutal clash.
They have continued to trade insults ever since ahead of a seemingly inevitable trilogy clash.
And such has been the level of vitriol in McGregor's recent behaviour on social media, he has been described as "falling into Jon Jones territory" by UFC analyst Chael Sonnen.
"Most recent, a week ago, I was irritated that Conor (McGregor) was deleting tweets. When you start tweeting late at night, high and/or drunk and then you delete them, you have now fallen into Jon Jones territory," Sonnen revealed on his YouTube video.
"There is nothing about Jon's career from a strategic standpoint that you want to mimic. Nothing. Go ahead and learn how he kicks the obliques, learn that spinning elbow, go right ahead.
"Not about career moves, you don't want to be in Jon Jones territory, right. Conor's fallen into that territory and I as a defender cannot come out and defend a guy who doesn't want to be defended."
McGregor has also hinted at a comeback in the boxing ring, after revealing he had only "two fights" left on his current deal with the UFC.
But the Irish star has been warned by linked rival Jake Paul that he must "sober up" to secure a crossover fight with the YouTube star.
"We're on the path to a lot bigger fights. I'm salivating too, because I'm just getting warmed up," Paul said at the post-fight conference. " Conor McGregor has a lot more to focus on besides me right now. I'm five wins in a row. He is one and three in the past four years.
"So the guy needs to get off of his little vodka or whatever the f*** his brand is, and sober up and start to get back in the f****** gym and then we can f****** fight.
"But to be honest, no way he hits harder than Woodley, he doesn't weigh as much as Woodley, he's shorter than Woodley.
"I said it before the fight, I think Woodley is a harder fight than him, especially on the way he's going, Conor's going down, I'm going up. Woodley came in game, we will see."
