Word of warning. This spell was made for Hettie, a CR 100 Spellcaster with 4595 HP, which could kill literally any CR30 homebrew. It was originally a level 33 spell. So, do Not use in a game unless the DM knows all of the information about the spell.

You summon a full-on spectral moon and drop it. It deals 1D1,000,000,000 (500,000,000) force damage, ignoring all resistances and immunity. All creatures you want to save have the ground surrounding them survive, and they take no damage. Carves a 2,000-foot spherical hole, except for the areas you save, which leaves a stable 2000-foot-tall rock spire, a 100-foot-tall, 5-foot-wide section has (AC 29 HP 1000 and succeeds on all saving throws) to knock over. When knocked over, deals (10,000,000/amount of rock spires left) bludgeoning damage