Warp Lightning

Clouds come and merge together above the target as a rift into the Realm of Chaos Opens. From it, a sickly green lightning emerges striking down at those beneath it. 

When you cast this, pick a point within range that you can see. (You must be outside or in an area large enough to accommodate large clouds, whether actual clouds or dust clouds.) When this spell is cast, all creatures within 30ft of the point you've chosen, must make a Dexterity Saving Throw or suffer 2d10 Lightning Damage and 1d10 Necrotic damage.

At Higher Levels. When you cast this spell using a spell slot of 4th or higher level, the damage increases by 1d10 for both Lightning and Necrotic for each slot level above 4th.