X0 Entities

X0 Entities are a race of aliens from the superjovian X0 (they have no names for their individuals or their species).

Physiology
X0 Entities are eukaryotes, but beyond that cannot be classified in any taxonomic system. They resemble roughly spherical green blobs a kilometer in diameter, and they move using hydrogen-filled gas bladders and spiracles covering their bodies. Due to this they weigh only 500 tonnes, far less than most organisms even approaching their size. They have no brains, but are somehow sapient. They are covered with a sticky mucus that they use to feed and build ships.

Diet
X0 Entities feed on aeroalgae, a supremely adaptive algal lifeform native to X0's atmosphere. As a result of their increasing population, the X0 Entities have spread away from their homeworld to cultivate aeroalgae. This unfortunately results in the death of all life on the farm world. The X0 Entities feed by using their sticky mucus to capture aeroalgae and then absorb them.

Reproduction
X0 Entities reproduce through budding. The newborn is 100 meters in diameter and grows to adulthood within a century. It shares all the memories of its ancestors prior to the birth of the next generation. For this reason they usually wait a million years or so before budding (to give their offspring a well-rounded worldview), and bud every millennium thereafter until their death. This results in millions of offspring.

Lifespan
X0 Entities are not immortal, but live for an incredibly long time. An individual that visited Mars before its destruction by a Reptalith colony was noted to have lived until the Ordovician, a span of 2.5 billion years. One of its descendants later expressed an admiration for Astraspis and found it amazing that it could have evolved into the present variety of vertebrate life over such a "short" time (equivalent to two decades from a human perspective). Despite this they seem to think at the same rate humans do.

Philosophy
Although they regularly commit genocide by "farming," X0 Entities find this to be a necessary evil, and would much rather find an alternative. According to one X0 Entity, it was at one point attempted to preserve races native to farm worlds, but this effort failed and was abandoned. They have spent billions of years trying to reduce the impact of their farming, but to this date have not succeeded.

Language
The X0 Entities communicate using pheromones in an extremely complex language that only they are able to understand fully. A Guardian Angel used telepathic technology to establish communication with an individual Entity.

Relations with other species
The activities of the X0 Entities have brought them into conflict with millions of races, most of which are now endangered or extinct (only so much of a population can fit on even the largest fleet of spaceships). X0 Entities notably despise Reptaliths for two reasons: they compete with the Entities for resources, and they have no regard for the victims of their hunger. More than once X0 Entities have attempted to save a world from Reptaliths with the promise that they would not use the world as a farm until the resident civilization died out, as was the case with Mars.

Technology
X0 technology mainly consists of mucus stars. These ships are 1600-km wide hollow spheres of crystallized mucus capable of opening Dimensional Rifts. X0 Entities also possess an unknown technology or physical feature allowing them to survive on terrestrial planets without collapse. When fighting is necessary, they create war prisms, dodecahedrons of crystallized mucus the size of humans capable of firing beams of concentated white light.