The Basement Phone
I used to work in a building that had three levels of sub-basements, with the piece of lab equipment I typically worked on in the lowest basement. I had the only key. There was a wired phone in there, and I did work late some nights… but not this night.
I was sleeping alone in my apartment when I woke up to a call on my cell phone from my girlfriend at 3 AM, she was in hysterics and asking why I scared her. Apparently she received a call from that basement phone just a minute earlier, with someone who sounded like me slowly repeating her name, until crackling and fading out. My apartment was 10 miles away from work. I thought she was lying, but I saw the 3 AM call from the basement phone logged on her cell myself. Still freaks me the fuck out.