During pro football season, New Orleans becomes " 'Who Dat' Nation." Fans open New Orleans Saints games with the signature chant and use it to rattle the eardrums of opponents during play.

Since the Saints' Super Bowl win in 2010, the phrase has popped up everywhere, from T-shirts to business names. Even people who don't watch football call themselves "Who Dats." But a messy legal question keeps rearing its head here: Who owns "Who Dat"?