Troblion is an autonomous spherical robot which rolls in an oval-shaped, partially irrigated sandbox. While it is rolling, it builds a layer of hardened sand on its outer surface. In this way, Troblion is able to change its appearance – its naked artificial skin gets hidden in a natural structure. But the more its layer grows, the heavier it gets. Finally, when Troblion is no longer able to move, it comes to rest to let the sand shell dry. Once the sand layer is dry enough, Troblion will start to shed the shell by deforming its silicon skin. Only then is it able to move again. The fragments which remain from the cracked sand layer are leftover pieces of gathered and re-assembled dust which indicate Troblion’s existence in time and space.