Ten self-described gamers have sued in US federal court to stop Microsoft’s purchase of Activision Blizzard. The suit, which cites the Clayton Antitrust Act, claims that the 10 plaintiffs will suffer “threatened loss or damage” through the deal. The complaint goes on to say that the new company will “substantially lessen competition” and “may tend to create a monopoly in various markets.”

While it’s unclear how this suit might proceed, it represents yet another roadblock in the Microsoft-Activision Blizzard saga. The deal, which would be one of the largest in video game history, has been awash in controversy from the start, with Microsoft offering Sony a 10-year licensing deal to keep the highly lucrative Call of Duty franchise on PlayStation platforms.

More recently, the Federal Trade Commission has sued to block the deal, citing concerns that it would harm competition in the video game industry. Previous reporting from the New York Post indicated that the FTC is largely split on whether to pursue such cases against large tech firms in gaming and otherwise, but it appears that the trustbusting side is winning as of late.

The FTC announced that Epic Games will pay over $500 million as part of a settlement to resolve alleged COPPA violations, among other allegedly unethical business practices. It’s unclear what exactly this climate means for the long-term viability of the Microsoft-ATVI deal, but some experts have already advised Microsoft to back off of the deal for its own interest–a path that Microsoft has roundly rejected.