Force lightning is an energy attack associated with the dark side of the Force in the Star Wars continuum. It is also known as Sith lightning. Force lightning is a directed discharge of Force energy from one or more of the user's limbs that causes extreme pain to the body, mind, and spirit, making it an extremely unpleasant and thorough form of torture. It can be used to electrocute someone nearly instantaneously with enough power behind it, and it has the distinction of being one of the only Force powers that can directly harm the Yuuzhan Vong. In the films, both Emperor Palpatine and Darth Tyranus use Force lightning on opponents, and it was one of the favoured Force techniques of the Mysterious Somebody, former ruler of the PPC.
Force lightning can be grounded on a lightsaber or absorbed and deflected or redirected by light side Force users with enough control and power. The Jedi Council forbids the use of Force lightning, though a few Jedi in the Star Wars Extended Universe have used it; while not inherently a power of the Dark Side of the Force, Force lightning was viewed as corrupting by Jedi of the Old Republic because of its association with anger and aggression.
It is impossible to use Force lightning without the ability to use the Force and it requires a high level of control. Victims of Force lightning often end up deformed and could end up permanently crippled, with a chance of brain damage, blindness or even massive calcification of the victim's skeletal system; a combination of the Mysterious Somebody's mind control and damage caused by prolonged exposure to Force lightning left Dassie Hyrax crippled for many years after the Reorganisation, and it was thought that he would only survive with the aid of the Medical Department.