Thundaja (Thunder IV)

You manipulate lightning aether to create a mass orb of electrical energy at a location you can see within range that hovers in place for the duration. Any creature hostile to you that moves to a space within 20 feet of the orb for the first time on a turn must succeed on a Dexterity saving throw. The creature takes 20 lightning damage on a failed save and half as much on a successful one. The orb vanishes when it has dealt a total of 80 damage.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the maximum total damage of the orb increases by 20 for each slot level above 5th.