void OnTriggerEnter(Collider other)
 {
     if (other.CompareTag(target))
     {
         //Debug.Log ("Choque con enemigo");
         other.GetComponent <health> ().changeHealth(damage);
         Instantiate(hitEffect, transform.position, Quaternion.identity);
         Vector3 dir = other.transform.position - owner.transform.position;
         dir.y = 0;
         dir.Normalize();
         Enemigo _enemigoScript = other.GetComponent <Enemigo> ();
         if (_enemigoScript != null)
         {
             _enemigoScript.AddImpact(dir, impacto);
         }
     }
 }