Shimmery sea sapphire disappears in a flash

An invisible car, I don't get.

An invisible animal, I get. That would be the best camouflage ever, just turn slightly to the side and go all Kate Moss on your predators.

The color is due entirely to the distance between crystals in the sea sapphire's back, causing it to look blue when seen directly on but to shift its 'color' appearance into the ultraviolet range when it tilts slightly and shortens that wavelength.

The full science is summarized in an article in New Scientist and originally in Journal of American Chemical Society.