Delayed Blast Ball Lightning

A bright orb of sparks streaks from your pointing finger to a point you choose within range where it lingers unless moved. When the spell ends, either because your concentration is broken or because you decide to end it, the orb of sparks emits a thunderous crack and discharges tendrils of lightning. Each creature in a 20-foot-radius sphere centered on that point must make a Constitution saving throw. A creature takes damage equal to the total accumulated damage on a failed save, or half as much damage on a successful one. The thunder can be heard from up to 300 feet away.

The spell's base damage is 4d12 lightning and 2d12 thunder. If at the end of your turn the orb has not yet detonated, the lightning damage increases by 1d6.

If the orb of sparks is touched before the interval has expired, the creature touching it must make a Constitution saving throw. The creature has disadvantage on the saving throw if they are wearing armor made of metal. On a failed save, the spell ends immediately, causing the orb to detonate. On a successful save, the creature can throw the orb up to 45 feet. When the orb strikes a creature or a solid object, or the orb takes damage, the spell ends, and the orb detonates.

As a bonus action, you can move the orb up to 15 feet in any direction. If the orb collides with a creature or a solid object, the spell ends, and the orb detonates.

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