Force lightning, also known as Sith lightning, was a power that Force users could conjure through the dark side of the Force.

Force lightning was an offensive technique which involved a discharge of electrical energy from the practitioner’s hands and was capable of killing or inflicting severe pain on the target, as well as possible disfigurement or even disintegration.

In some cases, the intensity of Force lightning was so high that the victim’s skeletal system glowed and could be seen through his or her skin—as demonstrated with Windu—or even through heavy armor. Luke Skywalker considered it to be the ultimate manifestation of the Force in a physical sense.

During the mission to Pasaana, while battling Kylo Ren, the Jedi Rey released a burst of Force lightning so powerful it was able to obliterate a First Order troop transport ship. Shortly after, during the Battle of Exegol, Darth Sidious unleashed a tempest of Force Lightning of such power and precision that it completely disabled an entire fleet of 14,000 ships, while leaving his own fleet of Xyston-class Star Destroyers untouched.

Could Darth Vader use Force lightning? Maybe! In the now Star Wars Legends book, Splinter of the Mind’s Eye, which was a story developed by George Lucas and author Alan Dean Foster, Vader duels Luke and uses the Force to create a ball of white energy to attack Luke. The comic adaptation of the story illustrates the energy as what definitely appears to be Force lightning. I don’t think we’ll ever see Vader using Force lightning in canon, but it certainly didn’t seem to be out of the question in 1978 when the novel was published. Although to be fair, it likely wasn’t yet established that Vader was more machine than man at that point.