Human Controller
From Wikipedia, the free encyclopedia
In the Animorphs series of science fiction children's books, a human controller is a human who has a Yeerk (an alien parasite) residing in their brain and controlling them. The Yeerk's control of the person is unnoticeable by other people; once the Yeerk enters the head through the ear canal and wraps itself around the brain, it controls the emotions, thoughts, memories and attitude so well that it is like nothing ever happened.
There is only one downfall to this system: once the yeerk has stayed in the host for 3 days it must leave their host to go to the yeerk pool containing kandrona rays which yeerks need to survive, thereby giving its host temporary freedom. The hosts are kept in cages for this time to await re-entry by the yeerks.
K. A. Applegate's Animorphs series
