Anyone Home?

Our surface expedition has reported back some astounding findings. The planet has multiple major cities, all abandoned but in quite good shape considering their age. The infrastructure and urban planning of each city is remarkably structured and harmonious, indicating a highly cohesive civilization driven by centralized, collective ideals - perhaps even a gestalt consciousness of some kind.

Based on the architecture and interior fixtures, the species that built all this seems to have been small fungoids, with a fairly low state of technical advancement. Where exactly they all went remains unknown.

Further studies of the lost civilization of … have given rise to more questions than answers. The plain, sturdy structures are thousands of years old, and all seem to have been constructed at roughly the same time, perhaps as brief as a single century. Similarly, any additions or renovations to the urban structure seemed to be done planet-wide at sudden, widely-separated intervals. The oddly-punctuated development of this society seems to show no appreciable change in population size.

A recent breakthrough shone some light on the vanished city builders of …. Apparently, the fungal species has a collective cycle of mass death and rebirth. They hatch en masse, almost simultaneously across the whole planet, and grow up as part of a linked hive mind collective. In the course of their hundreds of years long life cycle, they spread out and reclaim the cities built and abandoned by previous died-off generations.

When nearing the next death/rebirth event, they heed some species-wide biological clarion call. Through asexual reproduction they give birth to a pod that is buried in the ground. The parent dies, and the body decays and fertilizes the ground around the pod. After a long dormant period, the pods hatch, and the cycle begins anew.