PIS, short for "Plot-Induced Stupidity" is a term used to refer to events in a story that contradict a character's normal capabilities for the purpose of the plot. For example, if a generally competent, intelligent villain does something stupid like not killing the hero immediately when he has the chance, and that allows the hero to win, that would be an example of PIS (If the villain was just incompetent in general, it would be CIS, or short for "Character-Induced Stupidity" instead). - Thor being knocked unconscious by an ordinary gunshot. - Spiderman beating Firelord