It won’t work if your victim has caller ID, unless maybe you block your number. It works like this: Find someone who has two phones – say a work phone and a home phone. Pick a time when you know the target is near one of the phones and no one will answer the other. Call the phone that won’t be answered, then use three-way calling to call the phone that will be answered. When the target answers, say nothing but connect the three-way call. He’ll hear his own answering machine at home telling him to leave a message. Trust me when I say this will freak a person out