Have you ever heard someone laugh in a way that made you feel scared or uncomfortable? That's called an "evil" laugh. Some people use it when they want to be mean, or when they're pretending to be a villain in a story.
An evil laugh is usually deeper and slower than a regular laugh. It might sound like "Mwahahaha" or "Hehehehe." The person doing the evil laugh might also pause between laughs to make it seem more dramatic.
Sometimes, evil laughter is used in movies or TV shows to make the bad guy seem scarier. But you don't have to worry - it's all just pretend. In real life, most people don't use evil laughter, because it's not very nice. It's much better to use a happy and friendly laugh!