Answer:
Borg are a fictional species in star trek that assimilate beings into their collective, first injecting nanoprobes to assimilate the being from within. After a while, the nanoprobes install Borg implants and erase all traces of individuality and turn the victim into a cyborg drone. All drones are connected to a hive mind that controls them. The borg can also be fitted with interchangable eyepieces, mechanical arms, and different body parts and appendages. Borg are also able to assimilate and modify ships, as shown in Star Trek: First Contact.
See "Borg" at Memory Alpha for more info.