This is a story I heard from a friend. Yes, this is a true ghost story and it just happened days ago. (From the date of this article). A high school janitor thought he would offer some food one night. They offer food to the ghosts by just serving them outside, on a plate or in a bowl or something. The ghosts would come and eat them by sucking the energy force out of the food. After serving the food, he put small flags (or pennants) to notify that food is being offered. He placed the pennants around the school compound.
The next morning. The teachers went to school. The teachers' room was a mess. Apparently it was like a storm struck and blew everything out of place on the previous night. Same thing the next morning. It was like a hurricane but only the staff room was hit. If it was a real hurricane, the whole school building would have been destroyed.
They consulted a medium (a person who has knowledge of supernatural stuff) and the guy said that it was the janitor's fault. He offered food but placed too many pennants. The ghosts came, saw lots of small flags, thought that it was a big feast, went in and saw just a little bit of offering. The thought they were cheated and they got so mad they upset the staff room as a payback, and would do it every single night.
In the end, the school staff used the medium's suggestion, which was to cook a big feast and serve the food to the ghosts. That did it. Problem solved.