Sheet Lightning

Sheet Lightning is a runic spell that appears in Ultima Underworld I and II.

Description
The Avatar could first learn this powerful spell from a mage who had transformed himself into a door (an alteration he had -ironically- wrought in part due to his frustration with people repeatedly asking him how to cast Sheet Lightning). Using this incantation, the hero could release a vast cloud of electric energy into their immediate surroundings, striking all creatures unlucky enough to be in their vicinity.