The Nestene completely infused the planet, destroying all other life on it. It was far from a red star and had surprisingly little tectonic activity. Far in the future, it was invaded by the Time Lords attempting to stop the plastic asteroids from leaving. (PROSE: Synthespians™) The planet was destroyed during the Last Great Time War by the Dalek's Time Destructor. (PROSE: Natural Regression) The Darksmith Collective salvaged plastics from Polymos' wreckage in the 28th century to build a robot called the Agent. (PROSE: The Dust of Ages)