UV Sensitive Putty. After just a few seconds in the sun - or under the black light keychain (included) - this putty's icy WHITE shimmer is transformed to a vibrant PURPLE. Hold the UV light close to the putty to draw an intense line of color, or move it farther away for a PINK glow. Take it outside and watch it react! Then tear it in half to see the unchanged color in the middle. This non-Newtonian substance can be bounced, stretched, pulled, and snapped. Always returns to its original white color and never dries out. Glows ORANGE in the dark. The possibilities are endless!