North Carolina State University has developed a special wire shown here on headphones that can stretch up to eight times its original length while still delivering sound to the attached earbud.
The wire made from gallium and indium which is essentially a special liquid metal alloy. The only problem: If the wire's casing breaks, the liquid metal could leak out. In a NCSU research paper, they suggest that the liquid metal wire could also be used for gadget chargers or electronic textiles. This idea definitely has some possibilities!