They can call themselves the "12th Man" all they want, but they will never be THE 12th Man.
You must be referring to Texas A&M. They bring it up every year that they came up with the 12th Man idea first. They are particularly loud about it when Hawks have a good year. This however has been settled in a lawsuit. Seattle paid the university tens of thousands up front and $5000 a year to be able to use it. There are guidelines in how it can be used, but make no mistake about it the 12th man in Seattle is very real. Every visiting quarterback who was ever called for a false start, delay of game, or was forced into a time-out would agree.