Glimpse of the Void 2014

Muttering Void Speech, you force images of terror and nonexistence upon your foes. Each creature in a 30-foot cube centered on a point within range must make an Intelligence saving throw. On a failed save, the creature goes insane for the duration. While insane, a creature takes no actions other than to shriek, wail, gibber, and babble unintelligibly. The GM controls the creature’s movement, which is erratic.