My mother would tell a story about her time as a nurse.

She was working the overnight shift, walking through the hall. Apparently she had just check on an old man who's brain function had more or less stopped. She didn't get halfway down the hallway before she heard yelling. The old man had sat up in his bed pointing at the ceiling in horror. "Don't let that black thing get me, don't let that black thing get me!"

This continued for about 20 seconds before he was dead. I am worried, is that black thing always waiting for us to die or did that guy do something to deserve it? Was this real? What the fuck did he mean 'black thing' and how was he awake?