Death Nova

You target a humanoid corpse or undead humanoid within range, causing it to violently explode. Each creature within a 10-foot radius sphere centered on the target must make a Dexterity saving throw, taking 10d6 necrotic damage on a failed save, or half as much on a successful one. If the target was a corpse, it is destroyed, and if it was an undead humanoid, it takes additional 2d6 necrotic damage. The additional damage cannot be reduced by a successful save.

At higher levels, the damage of the 10-foot blast increases by 1d6 for each slot level above 3rd.