Sea sapphires could just be the coolest copepods you’ve ever seen (not seen) in the ocean. These creatures flash brilliant colors and then quickly move to what appears to be an invisible state. Scientists have been working to solve the trick for years.

It appears the color trick is not in the astoundingly perfect arrangement of hexagon reflective crystals beneath the exterior layer, but rather in the cytoplasm of the cells that contain them. Different thicknesses of this cytoplasm result in different reflected colors.

“The angle at which the light strikes the copepod affects the color of light reflected – or whether it reflects any light at all. In sea sapphires that appear to disappear, as the angle of light shifts from directly over the sea sapphire’s back to smaller and smaller incident angles, the wavelength of light emitted grows shorter and the color more violet until it shifts into the UV spectrum, making it effectively invisible to human eyes..”

Read the full article here.