A villain is a bad person in a story or movie who does mean, naughty things that make the main character sad or scared. They are like the person who takes your toys away or says mean things to you at school. But in stories, the villain is often a lot more powerful than the hero, and they try to stop the hero from winning in the end. They might have a scary face, a mean attitude, or even superpowers. Sometimes, the villain changes their ways and becomes good, but mostly they just stay bad and make the story more exciting.