void CmdThrowFireball()
{
GameObject instance = Instantiate(FireBall, transform.position + transform.up * 0.4f, transform.rotation) as GameObject;
instance.GetComponent <Rigidbody> ().velocity = instance.transform.forward * 10f;
FireBall ballScript = instance.GetComponent <FireBall>();
ballScript.initDamage(damage);
ballScript.InitID(gameObject.GetComponent <NetworkIdentity>().netId);
ballScript.SetOrigin(gameObject);
NetworkServer.Spawn(instance);
Destroy(instance, 5f);
}