Tildwin's Raging Bombardment

Choose a creature that you can see within range. The target must succeed on an Inteligence saving throw or be stunned for the duration. At the end of each of your turns the creature takes 8d6 psychic damages as long a it remains effected by this spell. At the end of each of its turns, the target can make another Intelligence saving throw. On a success, the spell ends on the target.

This spell ends if the person who cast it casts any other spell. 

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, you can target one additional creature for each slot level above 7th. The creature must be within 60 feet of each other when you target them.