Essaem's Instant Liver Failure

Essaem was known to create more peculiar spells, effective as they are. When you take damage from a creature within 60 feet of you, you can roll a number of their hit dice equal to their maximum hit dice, and add a number equal to their constitution modifier multiplied by their maximum hit dice, and they take necrotic damage equal to the total number rolled. They experience crippling pain in their abdomen as their liver is instantly destroyed, and they are unable to regain or replace their liver by any means, even divine intervention. The DM can decide if no longer having a liver would affect them beyond the effects of this spell.  A creature is immune to this spell if they do not have a liver.