Headless Hats

Headless Hats are a magical prank item created by Fred and George Weasley for their shop, Weasleys' Wizard Wheezes. They are small hats covered in pink feathers. When worn, the hat and head of the person wearing it, disappears. Although they are good for frightening people, they do not last very long. It works by extending an Invisibility Spell beyond the object itself, which is apparently unusual and advanced magic.