Mordenkainen's Tome of Foes lists a number of Demonic Boons (p. 30) that a DM can grant to monsters and NPCs dedicated to a particular demon lord. For Juiblex, it says that the "most dedicated devotees of ooze" gain the Slimy Organs trait. Part of the description of this trait states:
Whenever this creature suffers a critical hit or is reduced to 0 hit points, all creatures within 5 feet of it take acid damage equal to its number of Hit Dice.
Does this mean that if the creature with the boon has 12 hit dice, each creature within 5 feet of it takes 6 points of damage? Or am I misinterpreting this?