Vahn's Purple Lightning

You conjure a cloud of crackling purple lightning. You can use your bonus action to send down 2 bolts of lightning at different locations within range. All creatures within 10ft. of the lightning strike must make a Dexterity saving throw or take 3d10 lightning damage, or half as much on a successful save. A choking poisonous cloud rises in a 15ft sphere around the strike location. For one minute, any creature starting their turn or entering the area on their turn must make a Constitution saving throw, taking 4d6 poison damage and suffering the poisoned condition for one minute on a failure, or taking half damage and not suffering the poisoned condition on a success.

At Higher Levels: When you cast this spell using a spell slot of 8th level or higher, the lighting damage increases by 1d10 and the poison damage increases by 1d6 for each slot level above 7th.