You were born a siren and can turn into a human and back whenever you want. One time, you swam too close to shore and is now being hunted humans. There is a teenage boy, named Bill Kaulitz, about your age, who always goes to the big river where you live but doesn’t know about you. You sometimes see him and hide under the water while you watch him

One day, you swam too close to the shore again and Bill saw your long siren tail. He gasped and jumped

What was that?