Imperius Curse

"Total control. I could make it jump out the window, drown itself, throw itself down one of your throats..."

- Barty Crouch, Jr. as Alastor Moody

The Imperius Curse is one of the three Unforgivable Curses. When cast successfully, it places the victim completely under the caster's control, though a person with exceptional strength of will is capable of resisting it. The curse's incantation is Imperio.

Effects
The victim is placed in a calm, trance-like state in which all feeling of responsibility and anxiety is banished. They may then be directed to do anything the caster wishes, including crimes such as murder, political corruption, embezzelement, and so on. It is unknown if this hypnosis spell can affect physical capabilities, such as forcing a victim a task such as being stronger or casting spells far above their level.

As a victim feels completely relaxed, it might have the victim being able to conjure a Patronus, if the victim couldn't do so already.

Death Eaters made use of the curse in both the First and Second Wizarding Wars to force innocent people to do their bidding. For example, Lucius Malfoy used the Imperius Curse to force Broderick Bode and Sturgis Podmore to try to steal a prophecy from the Department of Mysteries in 1996, and Yaxley placed the Imperius Curse on Pius Thicknesse as part of the plan to take over the Ministry of Magic in 1997. Ironically, many Death Eaters had previously avoided imprisonment in Azkaban after Voldemort's first defeat in 1981 by in turn claiming that they had been under the Imperius Curse.

Resisting the Imperius Curse is possible, but requires great strength of will and character. Harry Potter, Barty Crouch Sr and Barty Crouch Jr each learned to resist the curse after being subjected to its effects.

Other Known Uses

 * Herbert Chorley, a Muggle Junior Minister, was the victim of a "poorly-performed Imperius Curse." The resulting symptoms included impersonation of a duck in public.

Etymology
This curse takes its name from the Latin imperiosus, meaning commanding, mighty, and powerful.

Imperius-Fluch