For the first time ever, scientists have made an invisibility cloak from silk. Current research focuses on medical applications for diabetics while visions of Harry Potter remain far afield. "The new metamaterial, as invisibility cloaks and their kin are technically called, only works on relatively long terahertz waves (a region of the electromagnetic spectrum between radio and infrared light), but the Boston-area scientists who developed the technology think that silk could work as an invisibility cloak at much smaller wavelengths, even in the visible range. The research could lead to a wide range of optically unique materials for use in biomedicine or defense."