Is there a way to make certain types of mobs weak to a certain types of weapons?

This is absolutely possible since I have no idea what you want. In the code I provide for you I am making giving an entity more damage.

    @SubscribeEvent
    public void livingDamage(LivingDamageEvent event)
    {
        DamageSource source = event.getSource();
        LivingEntity entity = event.getEntityLiving();

        if (entity instanceof YourMob && source.isProjectile())
        {
            entity.attackEntityFrom(DamageSource.GENERIC, 50F);
        }
    }

50 is A LOT if you couldn't guess. Also if you play around with the code, don't use a projectile as the damage source, otherwise, you will loop the code and crash. You will obviously change, "YourMob" to your mob. But otherwise, the principle is the same. You can do the opposite (make your entity strong) by simply healing the entity or canceling the event. If you want that let me know. Good luck 😁.

Ya no problem, I believe that MCreator registers all of their classes to an event bus. Can you send over all of your code?

Do you want the entities to be weak to your sword? Because this code only works for projectiles unless we specify it for your sword.

Basically, what do you want your mob to be weak to?

Yes, some things need to change. But this also allows us to do some really cool things.

So here is something simple (if the player used a diamond sword),

    @SubscribeEvent
    public void livingDamage(LivingDamageEvent event)
    {
        DamageSource source = event.getSource();
        LivingEntity entity = event.getEntityLiving();
        if (entity instanceof AnbuEntity && source.getTrueSource() instanceof PlayerEntity)
        {
            PlayerEntity player = (PlayerEntity) source.getTrueSource();
            if (player.getItemStackFromSlot(EquipmentSlotType.MAINHAND).getItem() == Items.DIAMOND_SWORD)
            {
                entity.attackEntityFrom(DamageSource.GENERIC, 50F);
            }
        }
    }

Or alternatively, we can make so the mob is weak to all of your weapons,

    @SubscribeEvent
    public void livingDamage(LivingDamageEvent event)
    {
        DamageSource source = event.getSource();
        LivingEntity entity = event.getEntityLiving();
        if (entity instanceof AnbuEntity && source.getTrueSource() instanceof PlayerEntity)
        {
            PlayerEntity player = (PlayerEntity) source.getTrueSource();
            if (player.getItemStackFromSlot(EquipmentSlotType.MAINHAND).getItem() instanceof SwordItem)
            {
                SwordItem item = (SwordItem) player.getItemStackFromSlot(EquipmentSlotType.MAINHAND).getItem();
                if (item.getGroup() == Main.TAB) {
                    entity.attackEntityFrom(DamageSource.GENERIC, 50F);
                }
            }
        }
    }

We can do some other things but this is a start.

Well, I don't know if MCreator even has a LivingDamageEvent. But you can just put that code in your mob class. For an MCreator procedure, I will check and get back to you.

And no, your procedure will not work for these reasons;

1. You're not calling an event. You need this procedure to execute when a mob gets damaged.

2. There are not enough conditions, even if you had the procedure to execute correctly. You are not checking for the DamageSource, therefore, all sources (fall damage, projectiles, anvils, cactus, etc.) will kill your entity.

3. I have no clue what "Current entity" is referring to.

No problem, that code works (I tested it). So if you have any issues let me know and we will fix it😁.

A simple way using MCreator's block code would be to

a. Make a procedure for attacks that have an if statement for the entity and make it deal damage

b. A, but with potion effects instead

c. A, but amplified by an enchantment