2-level Necromancy
Choose a creature that you can see within range. The target must succeed on a constitution saving throw or take 2d6 necrotic damage. At the start of each of its turns the target takes another 2d6 necrotic damage. The target can make another constitution saving throw at the end of its turn. On a success, the spell ends.
If the target dies while the spell is active they explode in a spray of blood, flesh and bones. All creatures within 5ft of the target must make a dexterity save. A creature takes 2d6 necrotic damage on a failed save or half as much on a success.
At higher levels: The damage increases by 1d6 for each slot level above 2nd.