counterclaimant

“Likewise, a Lanham Act claim might have been of assistance to the defendant-counterclaimant, if plaintiff's licensing attempts were sufficiently widespread to constitute "advertising or promotion.”

Patent claims as the basis for false advertising claims -- or not

“After 2 years of litigation, a DC trial judge dismissed all defendants on summary judgment and awarded one defendant-counterclaimant $18k+.”

Technology & Marketing Law Blog

“Possible answer, depending on the parties’ market positions also, of course, relevant to the antitrust issues: Lanham Act standing for false advertising requires a showing of likely harm, which means that the counterclaimant would have to provide reasons to think that sales were diverted from it in particular rather than from other competitors.”

False advertising doesn't violate the Sherman Act