You may think you've seen these before, but you haven't. Although traditional clear soap bubbles give you a rainbow effect in the right light, Zubbles are the first truly colored bubbles-nearly opaque, with a single vibrant hue. The problem, which took Minnesota toy inventor Tim Kehoe more than 10 years to solve, was to create a dye that could not only tint the thin wall of a soap bubble but that wouldn't leave a stain when the bubble broke. His solution: invent an entirely new dye that simply disappears.