The borg.

The Borg were a race of cybernetic beings, or cyborgs, from the Delta Quadrant. No single individual truly existed within the Borg Collective (with the possible sole exception of the Borg Queen), as all Borg were linked into a single mind. Their ultimate goal was the attainment of  'perfection' through the forcible assimilation of diverse sentient species, technologies, and knowledge. As a result, the Borg were among the most powerful and feared powers in the galaxy, without really being a true race at all. the borg captured other species and made them into borg, in TNG movie first contact the borg quoted " we are the borg, we will add your biological and technological distinctiveness to our own . your culture will adapt to service us. resistance is futile."