Custom damage to regular/common enemies and not bosses.

In my project, (ideally) I am trying to design a skill in which it only causes damage if an enemy is a regular or commonly encountered enemy.

Scenario:

- Player encounters normal enemy on world map. Casts Magic Spell. Causes 100 damage.

- Player encounters boss dude. Casts same magic spell, causes 0 damage.

I know this can be done through the custom formula, well I'm assuming through b.id==x, but manually inputting each enemy's ID I would surely run out of room.

Any suggestions or ideas. My usual google search didn't find the results I had hoped it would.

Thanks for any assistance.

You could set the boss to have 100% resistance to a certain 'element' so that the skill will not cause damage to them.

Genius! That worked perfectly.

In case anyone else needs to know further, I took Susan's advice by creating a 'Boss' element. In the skill, made the element 'Boss'. In the enemies feature tab, if a monster was a boss, State Rate 'Boss' = 0. 

During test battle regular monster was damaged and boss displayed 'immune'.

So simple...

Thanks!