Professional wrestling superstar Brock Lesnar's return to mixed martial arts made the UFC 200 that took place in Las Vegas last night (July 9) one of the biggest pay-per-view sporting events of the year. He entered the ring in grand fashion, using Metallica's "Enter Sandman."

Lesnar defeated Mark Hunt via unanimous decision, with all three judges saying he won 29-27. It was the first time he had fought in UFC since Dec. 30, 2011, when he lost to Alistair Overeem. Lesnar had been UFC's heavyweight champion from November 2008 until October 2010, when he lost a first-round TKO to Cain Velasquez. But that tenure as champ had also seen him struggle with diverticulitis, a condition that affects the large intestine.

In 2012, he left UFC to return to a career as a professional wrestler, which he had been from 2000-7. He held the WWE heavyweight title from July 2014 until March 2015. He also briefly pursued a career in professional football, participating in the Minnesota Vikings' pre-season training camp in 2004 as a defensive tackle. However, he was cut before the start of the regular season.

In the sports world, "Enter Sandman" has been best known as the entrance music for legendary relief pitcher Mariano Rivera, who won five World Series championships in his 19-year career with the New York Yankees. The band showed up prior to one of his final games at Yankee Stadium, presenting the future Hall of Faner with a giant autographed speaker with Rivera’s No. 42, the name Metallica and ‘Sandman’ on the front. The next summer, Metallica appeared in an ad for ESPN's SportsCenter looking for a new athlete to use one of their songs.