void Update()
    {

        Vector2 positionOnScreen = Camera.main.WorldToViewportPoint(transform.position);
        Vector2 mouseOnScreen = (Vector2) Camera.main.ScreenToViewportPoint(Input.mousePosition);
        float angleY = AngleBetweenTwoPoints(positionOnScreen, mouseOnScreen);
        Quaternion targetRotation = Quaternion.Euler(angleX*100, -angleY, 0f);
        Quaternion rotateTowards = Quaternion.RotateTowards(transform.rotation, targetRotation, Time.deltaTime * rotationSpeed);
        Quaternion finalRotation = Quaternion.Slerp(rotateTowards, targetRotation, Time.deltaTime * rotationSpeed);
        transform.rotation = finalRotation;
        angleX = targetRotation.y - transform.rotation.y;
}