Echoes of the Shadowfell

Visions of the horrors and echoes of the bone chilling screams contained within the shadowfell seep into the mind of your target. Constructs and undead are immune to this spell. The target must succeed a Wisdom saving throw or take 3d6 psychic damage and become frightened. On a successful save the target takes half damage and resists the fear effect. On the effected creatures turn it takes another 1d6 psychic damage. The frightened target may repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. 

At Higher Levels. When you cast this spell using a 3rd level spell slot or higher, the damage from the initial hit increases by 1d6 for each slot level above 2nd