In February, Stone Brewing, based in Escondido, Calif., announced it was suing MillerCoors for trademark infringement. In a press-savvy video, Stone Brewing co-founder and executive chairman, Greg Koch claimed the MillerCoors-owned Keystone was co-opting the “Stone” brand.

At the time, MillerCoors responded with a statement from media relations manager, Marty Malone, who said “This lawsuit is a clever publicity stunt with a multi-camera, tightly scripted video featuring Stone’s founder Greg Koch. Since Keystone’s debut in 1989, prior to the founding of Stone Brewing in 1996, our consumers have commonly used ‘Stone’ to refer to the Keystone brand and we will let the facts speak for themselves in the legal process.”

But today, things got real. According to Brendan Palfreyman, a trademark attorney with Harris Beach PLLC  in Syracuse, N.Y., who specializes in craft beer, MillerCoors struck back with an 82-page counterclaim and answer “requesting a ruling that it, rather than Stone Brewing, is the exclusive user of the word Stone,” Palfreyman said in a tweet.

Photo Credit: trademarkyourbeer.com

Palfreyman, who is also the creator and editor of trademarkyourbeer.com, operating under the umbrella of Harris Beach, published a blog post and Twitter thread recounting the counterclaim. In a series of tweets, he said, “MillerCoors gets right to the heart of it, alleging that [Stone Brewing] disassembled the Keystone Light mark to focus just on the word Stone, though some MillerCoors advertising indisputably uses the word Stone alone.” He continues, “[MillerCoors] also accuses [Stone Brewing] of using misleading images of Keystone cans in the complaint showing only the word Stone.”

The drama continues, with Palfreyman noting that MillerCoors “pulls no punches,” providing plenty of examples of “Stone” being used in Keystone branding (such as the “Keith Stone” character). In the end, Palfreyman notes, MillerCoors “seeks a ruling that it has the exclusive common law right to Stone in connection with beer”—meaning Stone would not be able to use the word “Stone.”

Will MillerCoors win on the merits? Palfreyman told VinePair that it’s difficult to say, since at the moment, all we have are the allegations of each side.

“The next phase in the lawsuit will be discovery, during which time each party can request documents and ask questions of the other in order to suss out the truth of the allegations,” he said. “I would say MillerCoors has an uphill battle to try to prove it has valid exclusive common law rights over Stone’s registration. MillerCoors has obviously known of Stone Brewing for a long time and, as far as we know, has not taken any action to make Stone Brewing cease and desist.”

Talk about throwing stones.