Phantasmal Killer

You tap into the nightmares of a creature you can see within range and create an illusion of its deepest fears, visible only to that creature. The target makes a Wisdom saving throw. On a failed save, the target takes 4d10 Psychic damage and has Disadvantage on ability checks and attack rolls for the duration. On a successful save, the target takes half as much damage, and the spell ends.

For the duration, the target makes a Wisdom saving throw at the end of each of its turns. On a failed save, it takes the Psychic damage again. On a successful save, the spell ends.

Using a Higher-Level Spell Slot. The damage increases by 1d10 for each spell slot level above 4.

You tap into the nightmares of a creature you can see within range and create an illusory manifestation of its deepest fears, visible only to that creature. The target must make a Wisdom saving throw. On a failed save, the target becomes frightened for the duration. At the end of each of the target's turns before the spell ends, the target must succeed on a Wisdom saving throw or take 4d10 psychic damage. On a successful save, the spell ends.

Using a Higher-Level Spell Slot. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d10 for each slot level above 4th.