This is a chilling experience a college classmate of mine went through back when we were students.

One night, he came running into my apartment. Pale as a sheet, looking like he had seen a ghost, he collapsed onto my floor. When I asked him what had happened, this is what he told me.

He was taking a bath and went to press the reheat button, but accidentally hit the call button instead. Right then, from outside the bathroom, he heard a woman's voice say:

"Hold on, I'm coming right now."

...or so he claimed.

He lived in a pretty nice apartment building, but since his family was out in the countryside, he lived alone, just like me. He didn't have a girlfriend, either. The moment he wondered whose voice that could possibly be, a chill ran down his spine, and he couldn't stop shaking. He was terrified to step out of the tub, but he couldn't escape the apartment without leaving the bathroom. So he hurriedly pulled his clothes back on and fled his place in a panic.

"Did you actually see a woman in your apartment?" I asked. Shaking like a leaf, he murmured, "I don't know. I was so scared I ran straight for the front door without looking around. But... the door was locked, and the security chain was on. I locked up myself when I got back from class. It was locked. I'm certain of it."

I ended up letting him stay at my place that night, but he refused to turn off the lights and drank like a fish, gulping down whatever booze I had in the fridge just to settle his nerves. After that, he went back to his parents' house, and his parents later came to move his things out of the apartment. I haven't heard from him since, so I have no idea what became of him.

Ever since I heard that story, I've been extra careful never to press the call button while taking a bath.