Caeliar

The Caeliar are an extremely advanced species who were accidentally responsible for the creation of the Borg. They were roughly humanoid in shape, but had bulbous heads, no noses and lipless mouths, as well as two segmented tubular protrusions that emerge from their skulls. They are able to temporarily merge their minds to form a Gestalt consciousness.

Caeliar technology is based on claytronic atoms, a form of programmable matter that grants them immortality and the ability to control their surroundings at the molecular level. The Caeliar use stable Omega molecules to power their city-ships.

The Caeliar civilization is united in the pursuit of the Great Work, a quest to make contact with a species more advanced than themselves in another galaxy to guide them through the next step in their evolution.

The Caeliar homeworld was the planet Erigol located in the Beta Quadrant. When the Caeliar were discovered by the human crew of the starship Columbia, the Caeliar refused to let them leave because they did not want other species to learn of their existence. Shortly after this, a feedback pulse from another galaxy destroyed Erigol. Many city-ships were flung back thousands of years back in time. One city-ship ended up in the Delta Quadrant, where a dying Caeliar forcibly absorbed the surviving Columbia crew into a defective Gestalt to preserve his consciousness, creating the first Borg Collective.