Below is an extract taken from http://www.xproject-paranormal.com/archives/paranormal/mara.html
"Another story was told by a man who said that he woke up
in the middle of the night because he had a hard time breathing.
When he opened his eyes, he saw a dark being sitting on him,
choking him. When he tried to move, he realized that he was
paralyzed. In his mind, he envisioned a cross, and immediately, the
being vanished, leaving the man gasping for breath. He also does
not fully believe that he had an evil visitor in the
night."
My mum encounter this thing a couple of times, at 1st I thought its
just a bad dream...but when I read bout it in a newspaper article,
I did a search on the net n found the site above. What is strange
is, she describe evrything exactly like the 1 above...a few days
later, 3 readers wrote in to that newspaper telling about having
the same experience. I would like to hear what u have to say about
this!!