You don’t see many featherweights beefing with heavyweight champions, but then again we’re talking about Conor McGregor.

The UFC featherweight champ has had a bit of an issue with Fabricio Werdum going back to some chatter about the latter’s base camp at Kings MMA in Huntington Beach, California.

In December, Werdum claimed McGregor had requested to stop in to train at Kings while he finished up his camp in California before facing Jose Aldo at UFC 194. McGregor’s manager denied the story, despite Werdum’s teammate and lightweight champ Rafael dos Anjos confirming it.

Now booked to challenge Dos Anjos March 5 at UFC 196, McGregor targeted the elite camp again during a press conference in Las Vegas. “Why would I want to train in that bum gym?” McGregor said. “[Werdum] needs to get his facts straight before I roll in there and buy that gym and turn it into a dump.”

Werdum didn’t take kindly to those remarks and later told reporters that he would have slapped McGregor had he been present.

Accepting the award for “Fighter of the Year” this weekend in Las Vegas, McGregor took another shot at Werdum, this time for pulling out of the main event of a card originally slated for pay-per-view.

“I need to feed all you bums,” McGregor told the audience of fighters and various MMA personalities. “I need to feed every single one of you in the game. I’ve got to keep working because you bums don’t work. We’ve got the heavyweight champion, who’s a pu**y, pulling out with a sore toe. How’s the heavyweight champion going to pull out with a sore toe? What kind of champion is that?”

It didn’t take long for Werdum to respond.