Have you read these irate Sylvester Stallone posts on Instagram? Fans of Sly and the Rocky movies might be surprised to see the star go full Italian Stallion on 93-year-old producer Irwin Winkler and MGM. “I really would like [to] have at least a little [of] WHAT’s LEFT of my RIGHTS back,” Stallone posted to his 15 million followers on July 18. And just today, reacting to the news that MGM is in early development on a Drago spinoff potentially with Dolph Lundgren, Stallone posted art of a bloodied Winkler and called him the “most hated, untalented, decrepited [sic] producer in Hollywood,” followed by “RETURN MY RIGHTS BLOODSUCKERS!”

So… what’s actually going on here? On the surface, it’s pretty simple: this is estate planning, Hollywood-style. Stallone, now 76, wrote and starred in the original Rocky in 1976, but he did not direct or produce the Oscar winner, and he assigned his rights in the script to the producers. Thus, despite all his success over the years (remember, he was in the $20 million club in the 90s), he has no ownership of his signature property. Winkler and the family of the late producer Robert Chartoff, along with MGM (now Amazon), control the franchise. That’s tough, but it’s the way copyright assignments work, and remember, Winkler and Chartoff famously mortgaged their own houses to get that first movie finished.

Stallone has wanted for years to change that arrangement, according to those close to him. Sure, he’s been paid a fortune for various starring, writing, and directing roles on the six Rocky films and two Creed spinoffs. (A third Creed is set for March.) But more money is more money, and Stallone—long known to be as intensely egomaniacal, financially-driven and, at times, angry as he is talented and business-savvy—would like he and his children to be paid more money, especially once he is no longer alive and the films, presumably, continue without him. That means ownership. And Winkler, I’m told, has made overtures to Stallone over the years to cut him in on the property. But the deals always fall apart over terms.