The southern rustcell replaced its ancestor, the thermo mold. Its most successful trait is it unicellularity, allowing each cell to collect the maximum amount of minerals possible. It no longer invests energy into plasmoidal reproduction, opting instead to simply let the wind and elements spread its species far and wide. If it does not land in an area moist enough, it will slow down metabolism, only resuming in more favorable conditions. It is most often underground, and so has lost its ancestor's "thermosynthesis".