ANFSCD: Strange Call

"Hello?" Jim groggily responded. But there was no one on the line. He was about to hang up, but a voice suddenly said "Stop." "Who is this?" Again, nothing. It was obviously someone playing a prank on him. And again, he was about to hang up, but then that same voice came over the phone. "Stop." Now this was freaking him out. He was only half awake, and that probably added to the weirdness of the situation. "Who's there?" Nothing. "Come on, this isn't funny. Who is this?" Nothing. "Ugh, fine." As he moved the phone to its cradle, he heard the voice again. This time it said "Don't hang up." But he hung up anyway. Then he went back to sleep.