Komar
The Komar were intelligent, non-corporeal, trianic-based energy beings that inhabited a dark matter nebula in the Delta Quadrant.

They were parasites who lived by absorbing the neural energy of other beings. They were able to inhabit the bodies of physical beings and had technology that could render a corporeal being non-corporeal, leaving their body essentially brain dead.

In 2371, Chakotay and Tuvok of the  encountered the Komar in their home nebula while investigating it from a shuttlecraft. Chakotay was separated from his body and Tuvok was possessed. He returned to Voyager and attempted to trick Captain Janeway into taking the ship to the Komar nebula. Fortunately, the disembodied Chakotay was able to help the crew uncover and defeat the impostor. ()

de:Komar
Non-corporeal species
Species