Denis George Mahan (born June 15, 1950), better known as Deney Terrio, is an American choreographer, host of the television musical variety series Dance Fever from 1979 to 1985. In 1991, he sued Merv Griffin, the show's producer, for sexual harassment; the US$11.3 million case was later dismissed.Terrio achieved fame as the dance coach and choreographer for John Travolta in the movie Saturday Night Fever.