Full disclosure: The following photographic illustrations are pretty terrifying. But if you are an art of photography buff, try and keep your eyes open while you look through them, because they're also really stunning.
There are groups of witches, and these groups are called covens. In the new film Hansel and Gretel Witch Hunters there goal is to stop a coven of witches from becoming immortal and ruling the earth. I think covens are magical because in groups people are stronger. Another reason is the witches all had to be together to preform the ritual.
Shadow people are supernatural shadow-like humanoid figures that, according to believers, are seen flickering on walls and ceilings in the viewer's peripheral vision. They are often reported moving with quick, jerky movements, and quickly disintegrate into walls or mirrors. They are believed to be evil and aggressive in nature, although a few people consider them to be a form of guardian angel. Hmmmm