UFC’s next big fight may be outside the Octagon as it escalates a bitter rift with a leading anti-doping agency.

The MMA property is creating its own drug-testing program and threatening legal action against the U.S. Anti-Doping Agency after the latter claimed UFC did “an about-face” on the status of Conor McGregor, as well as on their future relationship.

USADA has said that McGregor, like any other fighter, must spend six months in a drug-testing pool and pass two tests before competing. Having been out of the pool since 2021, he made his reentry on Sunday. McGregor was previously expected to fight in December, but his status has been in question because of the testing rules.