Citizens NPC set invisible?

Hello.
I'm using the Citizens API, I made NPC players but can't find out how to make the NPC's invisible.

Code:

                        final NPC bat1 = registry.createNPC(EntityType.PLAYER, p.getName());
                          final NPC bat2 = registry.createNPC(EntityType.PLAYER, p.getName());
                          final NPC bat3 = registry.createNPC(EntityType.PLAYER, p.getName());
                          bat1.spawn(p.getLocation().add(2, 0, 0));
                          bat2.spawn(p.getLocation().add(0, 0, 2));
                          bat3.spawn(p.getLocation().add(0, 2, 0));
                         
                bat1.addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, 100, 1));

I tried different ways like

Code:

bat1.getBukkitEntity().addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, 100, 1));

Code:

((LivingEntity) bat1).addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, 100, 1));

EDIT: Even throwing invisibility potions doesn't work, so I'll have to play with packets maybe?
Or maybe do like bat1.showPlayer() or hidePlayer()?
I have no clue as it's the first time I use Citizens, and i've been looking for hours.

Nevermind, works perfect with this.
https://bukkit.org/threads/entity-shown-only-to-specific-player-s.155715/
@Comphenix You're a god when it comes to developing, thanks!

EDIT by Moderator: merged posts, please use the edit button instead of double posting.