If Illinois were to come up with something original, would it be Otters?  What would work, a la Badgers/Wolverines, etc?  The 3 big schools in Florida all make sense.  Georgia has nothing original - the G from Green Bay and the bulldog from Yale.  Spartans is a great one, Gophers makes sense, if not strikes fear, lol.  
What would make sense for Illinois?  I've never been to that part of the country.