Simple question. It’s never clear if you can use the Steal Spell feature of the SpellThief on targets immunised to Sneak Attack.
Since you have to trigger a Sneak Attack in order to be able to trade it for steling spells, it is a fair question.
For example, I’m fighting an undead who cast spells. Its flat-footed for some reason, or I might just be able to flank it. Even if I could make a Sneak Attack, it wouldn’t deal any damage because undead are immune to this Extraordinary Ability.
BUT. Since all the conditions are met, can I still trade my Sneak Attack damage to use my Steal Spell Supernaturel Ability ?