Lower The Veil

8th-level divination

Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a strip of thin gauze or other sheer material)
Duration: Instantaneous

You briefly drop the veil of reality for selected targets, allowing a brief glimpse into the deep nothing beyond this realm to shatter their minds. Each creature you choose within 60 feet of you must succeed on a Wisdom saving throw or take 8d10 psychic damage and be driven insane for 10 minutes, per the symbol spell. On a successful saving throw, a creature takes half the damage and is stunned for 1 round. Creatures already suffering from insanity are immune to this spell. Blindness, however, is not a defense, since the experience is not sight-based, but an internal awareness.