Bone Blast

Necromantic energy fills the bones of a creature of your choice that you can see within range, causing them to explode violently and damaging the target and all within a 5ft radius. The target must make a Constitution saving throw. The target takes 8d8 slashing damage on a failed save, or half as much damage on a successful one. This spell has no effect on constructs.

corporeal undead have no saving throw against the damage 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.