A helium balloon is a type of balloon filled with helium, a lighter-than-air gas. When inflated, these balloons rise into the atmosphere because helium is less dense than the surrounding air. They are commonly used for celebrations, decorations, and events due to their buoyancy and colorful designs. Helium balloons come in various shapes and sizes, often made from materials like latex or Mylar. They can be filled with helium at party supply stores or with a helium tank at home. However, it's important to handle them responsibly, as they can pose risks to wildlife if released into the environment.