Eldritch Obliteration

Call upon the pure energy of The Great Old One. Choose one creature you can see within range. That target must make a constitution saving throw. Upon failure the creature will take 150 points of necrotic damage. If the creature succeeds on the saving throw, they only take 50 points of necrotic damage. This attack bypasses resistance and immunity to necrotic damage. If a creatures hp is brought to 0 by this ability, they are turned to dust. All items the creature is carrying, except for magic items, are also turned to dust. If there is left over damage from the first creature that is killed by this ability, the remaining damage will move to the nearest hostile creature to you. This ability ignores the spells maximum range, but cannot exceed 300 feet from the current target. The next creature that the damage is left over for must also make a constitution saving throw.  For each creature that the remaining damage carries over to, the constitution save dc that the creature must make is lowered by 2. This effect lasts until a creature succeeds on the constitution saving throw or the damage from the spell reaches 0.