Creepy stories

But then who was phone?

Working late in the lab at school, I had to grab something from an upstairs classroom. Its after midnight and the entire building was empty and dark. Suddenly the phone in the classroom starts ringing. So, after that heart attack I decide to answer it.

Silence. Not even a dial tone. So I hope out and go back to my dorm. The next day I have class in that room, so I ask my professor how often people call the classroom phone by mistake. He looks at me funny and says the phone in that room has been disconnected for years.