"That's a shark. It's a frightening shark heard by sailors all over the world. It is mysterious and fierce and very cunning. It will choose its own target. Once selected, it can be pursued for many years or even a lifetime until its prey. Until the mouth. The strange thing is that no one except the prey and his family can see it." The father said more and more excited, "Stefano, I'm afraid that shark selected you as long as you are on the sea for a day , It won’t let you go! You can’t go out to sea anymore!”So, the father immediately ordered to return to the port and let his son get off the boat, and then set sail again.Stefano stood on the shore. There was no boat shadow in the open sea, but when he looked at it, he found that a black shadow would appear on the surface of the sea after a while-it was "his" shark.