Xyience Xenergy, the official energy drink of the Ultimate Fighting Championship (UFC), inked a one-year endorsement contract with former UFC light heavyweight champion and UFC Hall of Fame member Chuck Liddell. The 43-year-old mixed martial arts athlete (MMA) will appear in the brand’s advertising, on its website and in its point-of-purchase materials, it says. Liddell also will appear in a series of unique promotions later this year, it adds.