The ghost.

I conjured the ghost tonight. She crossed over. I crossed over. Somebody crossed.
"I know what a ghost is... And I know what it isn't, too...it isn't a scarification or a flapping sheet, so pooh and pish to all THAT bunkum. What's a ghost? Unfinished business, is what." (From "The Satanic Verses" by Salman Rushdie.)
Unfinished business.
When dealing with ghosts, everything's the same - and everything's different. It's tricky business. You need to be at the top of your game. Every move could be your total downfall. Me? I'm a psychic weakling these days, I'm apt to trip over my Karmic shoelaces.