The cause of the horoscope belly button is the stump left by the umbilical cord. When the fetus is born, the umbilical cord must be cut when it is separated from the mother, resulting in a different belly button. There is no fixed shape. If you look at the shape of the belly button with the naked eye, it may be sunken, shallow, protruding, left, right, full moon, sea snake-shaped, perfectly round, etc. As long as the belly button is kept dry and clean. Don't often put your hands in and scratch it in daily life, otherwise you won't feel any discomfort.