Krawl

The Krawl are an alien race made of darkness, basically planet-devouring monsters with a faint sort of hive mind. There are usually four to five leaders of the Swarm, known as the High Krawl, and are solely responsible for the devastation of many planets, including the almost total loss of the Fubuki System. They appear to be made of some kind of coloured newtonian fluid, possibly liquid darkness.