Voodoo dolls are dolls that are used by Houngans (Voodoo priests) in curse rituals. It is well known that by stabbing a doll with a pin, the person who is the target of the curse is hurt in the same place as the doll.
Typically, voodoo dolls are made to resemble human figure using either rags or clay. Though in many cases, it is made in the likeness of the victim.
In reality, this kind of curse didn't exist in the original Voodoo. It is thought that the practice was imagined by the writer of some movie or novel. These dolls can be obtained easily as a souvenir in Haiti.