Unity (DC Animated)

From Multiversal Omnipedia

Unity was a collective alien life-form capable of controlling large numbers of people at once via the implantation of a tentacle-like extension of itself around the victim's brain stem. These creatures can be killed by concentrated X-rays. Via Reverend Howell, who was actually a different member of Unity's species, the creatures were taken from world to world, enslaving its peoples. However, when it reached Earth and tried to use Smallville as its staging ground- taking over the town's population in the process- it was defeated by Superman and Supergirl.