Karaoke is a form of entertainment in which an amateur sings along with recorded (or, sometimes, live) music using a mic and a public address system. The music is typically a popular song, minus the vocal track.
Enemies and rivals. These are not the same things at all. Enemies are made of equal parts of fear, loathing, and mistrust. The antipathy of rivals is often leavened with tradition, showmanship and good-natured posturing.