Hunter used to have a fear of balloons, and conquered that fear by inflating balloons. He now holds the Guinness World Records title for "Most balloons blown up in one hour by an individual". 
Hunter Ewen's audition in Episode 1306 consisted of giving the judges balloons, and racing against them to inflate the most balloons. Howie Mandel, Mel B, Heidi Klum, and Simon Cowell (Simon buzzed for a couple of them) all buzzed the act. All four judges voted "No", eliminating Hunter from the competition.