Defile

A sphere of dark, necromantic energy erupts at a point of your choice within range. Each creature in a 20 ft. radius Sphere centered on that point must make a Constitution saving throw, taking 7d6 Necrotic damage on a failure, or half as much on a success.

If the spell reduces at least one creature to 0 Hit Points, or if at least three creatures fail their saving throw, the spell cascades - choose one creature that was reduced to 0 Hit Points (or that failed its saving throw in the latter case). The necromantic energy erupts again in a 15 ft. radius Sphere centered on that creature. Each creature in the cascading area must make another Constitution saving throw, taking 4d6 Necrotic damage on a failure, or half as much damage on a success. This cascading energy cannot create additional cascades.

Using a Higher-Level Spell Slot. Both the initial and cascading damage increase by 1d6 per level of spell slot above 5.