You reveal horrifying facts about a group of targets in a 20ft cone, causing them to make a Wisdom saving throw, on a failed save they take 2d8 physic damage and are stunned for 1 round of combat or 1 minute out of combat. On a successful save they instead take half damage. 

The Stunned target makes a Constitution saving throw at the end of each of its turns, ending the condition on itself on a success.

Casting at higher levels: Each additional spell level adds a extra d8.