Who didn't have Silly Putty when they were kids?!? Silly Putty is the Crayola owned trademark name for a class of silicone polymers that is marketed today as a toy for children. It was originally created by accident during research into potential rubber substitutes for use by the United States in World War II.
It is sold as a 13 g (0.46 oz) piece of plastic clay inside an egg-shaped plastic container. It is available in various colors, including glow-in-the-dark and metallic.