An ’03 article called The Dark Backward: Demons in the Real World.
It is incredibly creepy, but worth a read:
A friend of one of the victims listed these manifestations: “He’d get an oppressive feeling. Sometimes he’d see a grotesque, impish figure, a short, really nasty-looking demon. When he described it to Rome’s exorcist, Father Gabriel Amorth, he said, ‘Oh, that guy.’ Other times, he’d just hear screaming. Deafening noise. I don’t know what you’d want to call it. The wailing of the damned.”
But there was one phenomenon that all the victims have experienced: “I could feel something there, looking at me.”
James felt that presence again on a visit home from college. He was awakened at 1:30 A.M. with the feeling that someone was approaching the front door. He went downstairs, and soon one of his sisters walked in, drunk. He talked to her in the living room, warning her about drinking too much.
That’s when the presence came. Then the strange thing.
The phone rang, and he picked it up. A female voice said, “Don’t even try to talk to her. Just leave her alone.”