I found this at WordPress talking about Dementors. This might be a mythological creatures or just a product of our imagination. But in reality, some people are becoming dementors by sucking off all our positive vibes within ourselves.

As i have said, we as humans are living in a pool of energies and as energies comes to human being it is transformed either good or bad. And these conditions differs from one another as to some bad is good for them and to other good is bad.

Let us all be aware of what we are becoming in our daily lives.