Astral Smite

Astral Smite causes Psychic trauma to the target and forces its soul from its body.  

The spell does 4d8 Psychic damage which ignores Psychic resistance/immunity.   

On a failed Wisdom saving throw it causes Astral Displacement; it ejects the target's soul from their body.  Their soul remains fully aware but their physical body is Unconscious. If their physical body dies while they are displaced the silver cord is severed and they will die in the Astral Plane. 

While displaced the target's soul is free to act but cannot affect anything not on the Astral plane.  The spell ends with a successful saving throw, if the caster loses concentration, or if the caster attacks the target.

Creatures without a soul are Immune to Astral Displacement.  This includes Constructs and most Undead.  

Githyanki, Intellect Devourers and Mind Flayers have Advantage on the saving throw vs. Astral Displacement. 

A willing target can choose to fail the saving throw.  

At higher levels.  For every additional spell level the damage increases by 1d8.