Ugin's invisible Flame

You breath gently. Each creature in a 60-foot cone must make a Wisdom saving throw. A creature takes 4d8 Fire damage and 4d8 Psychic damage on a failed save, or half as much damage on a successful one. Add 1d8 Psychic damage if you are invisible when you cast this spell.

A creature killed by this spell is surprised, and turned to ash.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8 fire, or psychic, for each slot level above 5th.