When i was secondary 4, i had a friend that got kidnap by a ghost. We were not sure what really happened at that time, but from my friend's experiences, he said that he was knocked out by someone.
When he was awaked, he found himself in a really old room. He did not do much, just a few seconds after he regain sanity, he was knocked out again.
He was found in the school the next morning in the canteen.