@Override
 protected void turnOff() {
   for (CostCharger c : invisibles.values()) {
     c.stop();
   }
   invisibles.clear();
 }
 @Override
 public void turnOffBuff(Player player) {
   // stop charge ticker
   CostCharger c = invisibles.remove(player.getName());
   if (c != null) {
     c.stop();
     // force visible
     for (Player p : Bukkit.getOnlinePlayers()) {
       p.showPlayer(player);
     }
   }
 }