The Undine (or commonly known as Species 8472) are tripedal and apparently highly xenophobic non-humanoid species. 8472 was first encountered by the Allied CR90 Corvette crew in the Gamma Nebula. The species originates from a dimension called fluidic space, accessible by quantum singularities. They are believed by the Borg to be the apex of biological evolution.
The Undine are a tripedal species and perhaps one of the tallest species encountered by the Allies. They do not possess vocal cords however do possess eyes which serve as their sensory organs. They are telepathic which they use to great effect in scanning the minds of other races and using it as a form of tracking mechanism when hunting enemy starships. The race uses their large arms in combat to great effect with a single strike being possibly fatal to any species known, this is in part due to their amazing immune system. Undine are perhaps the ultimate expression of biological perfection as they possess a near flawless immune system that attacks and destroys any form of 'infection'; both biological and technological. This was also the reason why the Borg failed in assimilating them. Undine use this to their advantage in melee by physically attacking their opponents, transferring blood and immune cells to their target. Victims of such strikes can be best described as being 'eaten alive' as the immune cells from the Undine are transferred to its victim which begin to destroy its new 'host'.