Large Annelid that Propagates, and Thrives in, a Sandy Environment
This creature seeks t perform two basic roles. 1: processing of dispersed materials into easily-harvested and valuable parcels. 2: Preprocessing of planets for terraforming.
To achieve the first, they grow into massive creatures, consuming the terrain, and storing heavier particles, which are slowly infused with psychic energy before being deposited on the surface.
The latter relies upon a ludicrously environmentally-tolerant biology and a life-cycle that involves a potentially permanent larval-stage that stores water and converts solar energy into chemical energy that is seeded into the ground for consumption by adult and increased arability.
In larval form, they are a small cluster of black grasses with a large bulb with a rapid-growing root that digs directly down until it hits an obstacle, which it wraps around until it meets with sufficient other roots to tear the obstacle apart, thus deepening the surface layer by destroying the rocky layers beneath. The roots automatically sever if pulled upon, allowing them to be consumed, and will periodically sever of their own accord to be driven down by a new root system. If the roots go undisturbed for long enough, the larva will have an increasing chance to transition into a initially rapidly-growing worm that will dig into the ground and begin harvesting.
The creature's biology is of very low complexity, with almost no distinct organs while being heavily segmented. It's "mind" is spread across its entire body, composed of psychic brain matter. The very low density results in a very slow mind, but its massive volume results in a very powerful mind which is primarily focused upon reinforcing its own vital functions, making it extremely resilient. The immense psychic field also soaks its contents in psychic energy, thus the material it deposits is extremely psychic ally active, and can be used to enrich psychic profiles, allowing for some common strains to gain the psychic profiles of royals, albeit with none of the physical or mental benefits of royalty and a high mortality rate amongst candidates. The influx of expendible forces to maintain the psychic requirements of field-equipment though would be of great value even if they will never be true royals.
The result of an established colony should be accumulation of surface-water, deep, rich, sandy sol, sufficient heavy elements in the larval colonies to sustain life, and enough biomatter for more conventional ecologies to get started. Hopefully they would also transition the atmosphere to a more familiar one, but other agents could perform that with the provided head-start, and the priority here is to survive in any atmosphere, rather than to perform the specific processes to alter one specific chemical composition to another...