Space Posura did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Space Posuras are enemies that appear in Kirby Mass Attack and Kirby Mass Attack 2. They resemble their non-alien cousin, Posura, but completely blue.
Space Posura move across asteroids, moons and other celestial objects in space around the Popopo Islands,instead of shooting Posura jelly from it's rhinophores, however, they fire electric balls that float around for a bit, if a Kirby touches it, they will be disintegrated into a Blue Kirby. They are about as weak as a normal Posura.
Kirby Mass Attack 2
In this game, they inhabit the Asteroid Maze in Stage 11 of the new island, Steampunk Sky.