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. This makes it unique among the unforgivable curses, as it is the only one of them with a known, reliable method of resistance. The curse's incantation is Imperio.
Effect: If the target is of weak will, they will be confused, dazed, or maybe even put under the complete domination of the caster. The caster will be made more evil by each use of this spell.