They cartwheel. They punch. And they are overturning centuries of tradition.

Nate Diaz and Jorge Masvidal both called for an immediate rematch after a doctor stopped their fight because of a bloody cut. Like that fight, it wouldn’t be for a championship.

A president facing a fight of his own decides to watch one at Madison Square Garden.

Nate Diaz, who fights this weekend at Madison Square Garden, is one of the U.F.C.’s top draws. The promotion isn’t as deep when it comes to stars for the future.

Despite what the fighter himself suggested on Thursday, officials said he had not violated antidoping policy.

The fighter said he did not know what substance he tested positive for, but claimed he would be unable to face Jorge Masvidal. Conor McGregor has volunteered to take Diaz’s place.

A second complaint came as the mixed martial arts star waited to see whether prosecutors would charge him in another case.

Ariel Gandulla returned voluntarily from Canada this week to face charges of murder, conspiracy and kidnapping in Miami-Dade County, Fla. Four other men have been charged in the case.

After a three-year hiatus, the pot-smoking, Dana White-antagonizing Everyman returns for a (co-)main event.

A week after the challenge exploded across the internet, it has taken on a life of its own.