Before Rory McIlroy became a back-to-back Masters champion, he handed his golf bag to a pop star - and the internet got one of its favorite sports crossover moments. At the 2015 Masters Par-3 Contest, One Direction's Niall Horan served as McIlroy's celebrity caddie at Augusta National. The pairing of a global music star and the world No. 1 golfer was already drawing cameras. Then Horan slipped on pine straw, right before an on-camera interview, and the moment became a widely shared clip that fans still revisit more than a decade later.