Mind Control Headbands are devices that appeared Ben 10: Ultimate Alien. They are used to control the mind of another.
Mind Control Headbands are used to control minds. At least two will be used in tandem, one worn by the controller to instruct the controlled and one worn by the controlled to receive instructions from the controller.
A single controller can control multiple individuals. If multiple individuals are controlled, they will still retain a degree of autonomy such that they can act independently of one another, but will not have the ability to control themselves.
As shown in Ultimate Aggregor, Mind Control Headbands are easy to break.
Dr. Animo's Mind Control Headband
In Escape from Aggregor, Dr. Animo used a Mind Control Headband to control of the mind of a yeti and used it to fight Four Arms. The yeti was simply a distraction while he prepared his de-evolution bomb to turn the world into yetis. When Four Arms turned into Brainstorm, he used his powers to take control of the headband and make the yeti attack Animo. After Animo was defeated, Brainstorm released the yeti from the headband's control.
In It's Not Easy Being Gwen, Dr. Animo used the Mind Control Headband again to control his giant mutant frogs.
Aggregor's Mind Control Headband
In Ultimate Aggregor, Aggregor used a Mind Control Headband to control Bivalvan, Ra'ad, P'andor, Andreas and Galapagus to attack Ben, Gwen, Kevin, and Grandpa Max while he readied Paradox's time-machine to absorb the aliens' powers. When Kevin and Max smashed Bivalvan's headband, he was freed from control, but was transported back to his pod. When Ra'ad was squeezing Ultimate Swampfire, Ultimate Swampfire changed into Nanomech and destroyed his headband as he transported away. The same thing happened to the others.