Nie działa
public void spawnWitherRed(Player p){
Wither w = (Wither)p.getWorld().spawn(p.getLocation(), Wither.class);
w.setCustomName(ChatColor.RED + "Boss RED");
w.setCustomNameVisible(true);
w.addPotionEffect(new PotionEffect(PotionEffectType.SLOW, 999999999, 1000));
w.addPotionEffect(new PotionEffect(PotionEffectType.BLINDNESS, 999999999, 1000));
w.addPotionEffect(new PotionEffect(PotionEffectType.WEAKNESS, 999999999, 1000));