Sequids
Sequids are an alien race with a mindless hive like mentality. They can only exert power when attached to a host.
Sequids are a uni-minded race with great powers of mind control. Without a host they are effectively mindless. There are certain races, such as Martians and Viltrumites that the Sequids are not able to bond with. The Martians have used to their advantage and enslaved the Sequid race on their planet.