@EventHandler(priority = EventPriority.LOWEST)
public void onPlayerDrop(PlayerDropItemEvent e) {
SpoutItemStack sis = new SpoutItemStack(e.getItemDrop().getItemStack());
if (!sis.containsEnchantment(SpoutEnchantment.UNSTACKABLE) && sis.isCustomItem()) {
CustomItem ci = (CustomItem)sis.getMaterial();
if (!ci.isStackable()) {
sis.addEnchantment(SpoutEnchantment.UNSTACKABLE, 1000);
}
}
e.getItemDrop().setItemStack(sis);
}