You call forth the powers of the elder things to drain the very essence of life from your enemies. Any creature in a 20-foot cone originating from you must make a Constitution saving throw or suffer 3d6 points of Necrotic damage.

The creature's Maximum Hit Points are reduced by half the amount of damage for 24 hours, rounded up. Additionally, you gain Temporary Hit Points equal to half the damage dealt. If a creature succeeds on the saving throw, they suffer half the damage with no other effect.

For every spell slot level used to cast this spell beyond 2nd, the damage increases by 1d8 and the cone increases by 5 feet. If you cast this spell at a 5th level or higher, your next cast of Eldritch Blast until a short or long rest automatically hits and deals maximum damage.