Corpse Explosion

This spell causes one tiny, small, or medium pile of bones, corpse, or undead creature of your choice to explode in a shower of bone splinters, gore, and necromantic energy. This destroys the pile of bones or corpse and destroys the body of the undead creature if this spell reduces it to 0 hit points. An undead creature not currently controlled by you must make a Constitution saving throw, not exploding on a success but taking 1d12 necrotic damage and exploding on a failure. The explosion’s area of affect is determined by the pile of bones’, corpse’s, or undead creature’s size and measured from its edges; anyone standing on or within a pile of bones, corpse,or undead creature’s space is included in the explosion and rolls their save at disadvantage. Damage is determined by the size of the pile of bones, corpse, or undead creature.

             Target's               Explosions       Necrotic
               Size                Area of Effect     Damage
                Tiny                 shared space        3d4
               Small                     5 feet              3d6
             Medium                   10 feet             3d8
               Large                    15 feet             3d10
               Huge                    20 feet             3d12
          Gargantuan                25 feet             3d20

Each creature within the explosion, must make a Constitution saving throw. A creature takes necrotic damage as detailed previously on a failed save, or half as much on a successful one.

At Higher Levels. You may target two piles of bones, corpses, or undead creatures at 3rd level or higher, three targets at 5th level or higher, four targets at 7th level or higher, and five targets at 9th level or higher. If you cast this spell using a spell slot of 4th level or higher your target can be large, 6th level or higher your target can be huge, 8th level or higher your target can be gargantuan.