CHICAGO - Opponents of University of Illinois mascot Chief Illiniwek sued the school's trustees Tuesday, claiming the buckskin-clad figure perpetuates a racial stereotype. In its lawsuit, the Illinois Native American Bar Association and two individuals seek to force the school to stop using the Chief as its sports mascot. "The use of this mascot is outrageous. It's been going on way too long and it should come to an end," said Kim Edward Cook, association president. The Chief is a 78-year-old tradition in which a student dresses in buckskins and headdress and dances at sports events.