Mind control is a common occurence in science fiction and fantasy. The methods vary, including psionics, drugs, parasitic creatures, technological devices (generally cybernetics in the case of science fiction) and magic. Regardless of method, mind control allows one person -- typically a villain -- to control the thoughts and/or actions of another.
The degree of control also varies, ranging from subtley influencing a person's behavior to permanently altering their personality. In most stories, the degree of control is somewhere in between, forcing the victim to take actions he or she would normally never do without actually making them "willing" participants in the act. Victims are often able to resist the control to some degree, even "snapping out of it" if the controller attempts to force them into a particularly despicable act.
Mind control differs from possession in that the controller typically remains separate from the victim and can continue to engage in other activities while controlling the victim's behavior.
- In the Foundation Series, the Mule was capable of adjusting the emotions of other people, making them his loyal servants. The Second Foundation possessed similar abilities.
- In X-Men, Professor Xavier controls the actions of the villains Sabretooth and Toad with his telepathy.
- Star Trek II: The Wrath of Khan, Khan uses alien parasites to gain control of Chekov and Captain Terrell.
- In Star Wars, Jedi can employ a "mind trick" with the Force to influence the behavior of others.
- Telepaths in Babylon 5 could engage in varying levels of mind control, depending on their telepathic strength.
- In Code Geass, Lelouch's geass power allows him to make anyone obey his orders, though it can only be used once per person.
- In Mass Effect, the Reapers use a form of mind control known as "indoctrination". This process takes time and decreases the lifespan of the controlled individual. Reapers can vary the degree of control, as victims of indoctrination become less competent with tighter control.
- In The Avengers, Loki had a staff that could make someone into a loyal servant via contact.
- In Agents of SHIELD, Hydra has a brain-washing process to make victims "compliant".