Dreamcatcher is considered by filtering dreams to the local American Indians.
Bad dreams are taken from the net, and good dreams allowed to go through since good dreams know the way through the net.
That slipped through the central hole and then gently slide into the mind of those who sleep. The bad dream don't know the way, they are trapped in the net, and then disappear at dawn. With the ancient Indian culture, dreamcatcher also has its own legend, although different tribes have different legends, they all have the same symbol-retain good dreams and best wishes.