I wanted to make zombies & skeletons take damage from the potion effect poison. how would i make that?

Well, this is gonna be hard.

    public boolean isPotionApplicable(PotionEffect p_70687_1_)
    {
        if (this.getCreatureAttribute() == EnumCreatureAttribute.UNDEAD)
        {
            int i = p_70687_1_.getPotionID();

            if (i == Potion.regeneration.id || i == Potion.poison.id)
            {
                return false;
            }
        }

        return true;
    }

 

This is code that handles adding poison/healing potion effect depending if mob is UNDEAD.

Code is called directly from EntityLivingBase so editing it is ONLY possible for your own mobs (non-vanilla).

 

ASM is a bit overkill here (also - might be hard if you don't know it) and I don't think there is an event for potions - you might wanna do request for "onAdded/RemovedPotion" but it's very small thing, so idk if it'll get done fast.

 

Note: My opinion, there still might be some trick for that.

EDIT

There is ofc way to totally pawn this issue - by overriding Zombie with CustomZombie extending Zombie, but you know - comatybility might get harassed here (not always, but often).

Ok I'll let it be... but thanks for your answer