Chaos bomb (fixed ver.)

You summon a glowing purple ball and throw it towards any creature or object within 20ft of you. Upon impact, every creature within a 10ft radius of the impact point must make a Dc 17 dexterity saving throw or take 6d8 necrotic damage and become stunned. Even if this spell misses or a creature's save succeeds, it still does 1d4 necrotic damage provided that the creture is within 5ft of the impact point.

When you cast this spell at 5th level or higher it gains 2d4 additional damage per level above 4th. If this spell is cast at 6th level or higher, it adds a -3 to the next roll of the creature closest to the impact point.