The invention of Silly String was a complete accident that nearly didn't happen. In 1972, inventor Leonard A. Fish and chemist Robert P. Cox set out to create an aerosol spray that would act as an instant cast for broken limbs. After dozens of tests, they came upon a nozzle that emitted a consistent string, which shot about 30 feet across the room. Inspired, they decided to turn their invention into a toy. The rest is history. Silly String is a registered trademark of Silly String Products.