JAWS may well be one of the few perfect scores written for a film and works ingeniously well while at the same time stands on its own as a serious musical work. The main "shark" theme, a simple alternating pattern of two notes became a classic piece of suspense music, synonymous with approaching danger. Williams described the theme as "grinding away at you, just as a shark would do, instinctual, relentless, unstoppable." The piece was performed by tuba player Tommy Johnson. When asked by Johnson why the melody was written in such a high register and not played by the more appropriate French horn, Williams responded that he wanted it to sound "a little more threatening".