Alien head suckers are small villains, who can take the control of any human of animal by biting the back of any head.
These creatures appeared in Team Galaxy episode: Class of 2051. When Josh, Brett and Yoko were in space, their ship went inside of big long space road. They didn't know what was that, but they still continued to go forward. When they came back on Earth. They saw that all people were mind controlled by Alien head suckers. Team understood that came in future, when they were inside of big space road, and they came in time, when world were attacked by these alien insects. Later. These creatures saw that this team was not under control of them, so they start to attack them. Team tried to escape and find a place where they can hide.
Later, they knew how to stop insects, but they didn't see that Brett got under control of one of alien head suckers. Yoko, Josh and their robot Fluffy left only. They decided to separate. Fluffy went to machine, which was creating the shield around city, to protect aliens from rains. When Fluffy turned off the power, there were still no rain, and one alien took control of Yoko. Josh was only one left, but in moment, there were a rain and all aliens were dead. Later, team returned back in their time to stop aliens from invasion.