Scientists have succeeded in creating simple cell-like robots that join together in large groups, move in a coordinated fashion and transport objects. They are able to coordinate their movements, transport objects and even respond to light. Scientists call them'particle robots' but even their creators admit they share similarities with the'grey goo' that prompted a famous warning from the Prince of Wales. Grey goo is a hypothetical end-of-the-world scenario involving molecular nanotechnology in which self-replicating robots consume all biomass on Earth. Scientists have succeeded in creating simple cell-like robots that join together in large groups, move in a coordinated fashion and transport objects.