8472 evolves into another dimension, the fluidic space, which is filled with an unknown matter. Their DNA is the most complex ever encountered by the Borg and the Federation (one of their cells presents 100 times more organic data than one Human cell). They are able to create singularities to travel from one dimension to another. Their vessel is totally organic. Although very advanced, the 8472 seem to be limited in their goals through space conquest. They are indeed only interested in purging, considering any other being as inferiors, as parasites. They are thus very similar to the Borg. The Borg are helpless against them, they can not assimilate them because of the complexity of their genome.
After the Borg attempted to assimilate them without success, 8472 undertakes a counter-attack to eradicate these harmful cyborgs. The species easily succeeds in destroying the cubes of the Borg, and even their planets. But the Federation intervenes through the USS Voyager and gives to the Borg the means to annihilate 8472 in order to cross their territory safely. It will be missiles loaded with nano-probes which will put out of use 8472. The species will withdraw towards its native space. This will cause disagreements within the USS Voyager crew.
A being among the 8472 will be left behind and hunted by Hirogens hunters.
Subsequently, 8472 will consider humans as even more dangerous than the Borg and will develop an offensive against the Earth.
The 8472 are 3 meters high and have three feet. Their eyes have pupils in the shape of crucifixes. They have no mouth, no navel, no ears. They are strong enough to cut humanoids into pieces. They do not need atmosphere, oxygen or gravity to survive and move. They do not sleep.
The 8472 communicate by telepathy. The Ocampas and the Vulcans are able to discuss with them.
They are the only ones living in the fluidic space, hence they hate all other species and worship extermination. They wish to exterminate all life in the milky way after the penetration of their territory by the Borg.
They have technologies that allow them to take other forms of life.