Do Mystic's Disciplines function like Spells for the purpose of Sneak Attack and and Assassinate ability? Cause the stipulation is, "The next attack you make with it before the end of your turn ignores the target’s armor, requiring no attack roll" meaning there is a weapon attack action so can I apply SA?
Ethereal Weapon (1 psi): As a bonus action, you temporarily transform
one weapon you’re holding or your unarmed strike into pure psionic
energy. The next attack you make with it before the end of your turn
ignores the target’s armor, requiring no attack roll. Instead, the
target makes a Dexterity saving throw against this discipline. On a
failed save, the target takes the attack’s normal damage and suffers
its additional effects. On a successful save, the target takes half
damage from the attack but suffers no additional effects that would
normally be imposed on a hit.
Best Answer
Just like in your other question, whether it's a spell or not has nothing to do with whether these features work. What matters is that you make an attack. Sneak Attack requires you to use a weapon for the attack:
While Assassinate just requires an attack:
But with Ethereal Weapon, you're not making an attack. You're forcing the target to make a saving throw. The PHB includes a very straightforward statement for questions like this:
Therefore, regardless of the fact that you're using a weapon, you aren't making an attack, and these abilities cannot trigger.