While the cellos provide the rhythm, the quote 'You're gonna need a bigger boat' in 'Jaws' is punctuated by the thundering presence of the tuba. John Williams used the tuba to provide the 'weight' of the Great White Shark. The tuba is the largest and lowest-pitched brass instrument. Williams had the tuba play the two-note motif in a way that felt like a predator's heavy breath. Interestingly, the tuba player, Tommy Johnson, initially thought the part was too simple, but Williams insisted that the 'simplicity' was what made it terrifying. This choice turned the tuba from a 'clumsy' orchestral instrument into a symbol of aquatic horror. It remains a legendary example of how a single brass instrument can define the power and scale of a cinematic monster and its most iconic lines.