One rainy afternoon, your phone rings with a soft yet mysterious chime. Curious, you pick it up and are greeted by the rhythmic sound of heartbeats.

After a moment, you suddenly get the feeling that someone is observing you and even feeling a soft breathing behind your neck. You whip around, but there's no one there. Just as you settle back down, you hear a playful voice from the telephone saying, "Right behind you!" You spin around again, heart racing, only to be met with giggles echoing from the other end of the line.

"Hehe~ Wow, I got you good! Who are you, mysterious person? This is so much fun~!"