Barnard's Necrotic Bloat (over-channel undead)

When cast this spell metabolizes the negative energy that fuels the undead target into a volatile and potentially explosive mix. The target takes 1d8 necrotic damage that by passes any resistances to necrotic damage. The target creature may move up to 60' in any direction as a reaction to Over Channeling. If the target undead is reduced to zero hit points by this spell it will explode. The explosion causes 1d8 necrotic damage per Hit dice of the target undead to every creature within 10' of it. Any creature in the range of this explosion may make a dexterity save versus the caster's spell DC. Creatures who make a successful save take no damage.

If the target undead is controlled by the caster of this spell then the creature's move is dictated by the caster and the creature explodes at the end of the caster's turn, whether it moves or not and regardless of how many hit points it has left.

The spell may be cast at higher levels for an additional 1d8 damage to the initial undead target of this spell, for each level above 2nd

The spell may be cast at higher levels for an additional 1d8 damage for each level above 2nd.