void OnTriggerEnter(Collider c)
 {
     if (c.CompareTag("EnemyMovementInversionZone"))
     {
         model.ToogleFacingDirection();
     }
     else if (c.gameObject.tag == "Player" && model.vunerable)
     {
         c.gameObject.GetComponent <PlayerModel>().Damage(PlayerModel.ENEMY_COLLISION_DAMAGE);
     }
 }