Now you see it, now you don't. But the disappearing act performed by this small sea sapphire isn't magic: it manage to flex its body to reflect frequencies of light that the human eye simply can't see.
As New Scientist reports, sea sapphires come in an array of different colours, including this electric blue. But their colour is defined by the spacing of guanine crystals and cytoplasm that lurk within the cells across their back, with the distance relating to certain frequencies of light. When the creature tilts itself away at 45 degrees to the viewer, the light being reflected shifts from bright blue to ultraviolet — which is beyond the visible range of light for humans. The researchers who spotted the effect reckon that the findings could help inspire new kinds of coating for glasses, mirrors and displays.