Darkness Hungers

You call forth a magical insatiable darkness from the Shadowfell to devour your enemies. The darkness surrounds you in an Emanation of 5 feet for the duration and spreads around corners. A creature with darkvision can't see through this darkness, and nonmagical light can't illuminate it.

whenever the Emanation enters a creature’s space and whenever a creature enters the Emanation or ends its turn there, it must make a Constitution saving throw. On a failed save, the creature takes 2d6 necrotic damage. On a successful save, the creature takes half as much damage. 

Any time a creature is killed within the area the darkness siphons some life energy to protect you, granting you temporary hit points equal to 1d4 plus your spellcasting modifier.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 and the temporary hit points increase by 1d4 for each slot level above 3rd and the temp hit points increase by 1d4 for every 2 levels above 3rd (2d4 at level 5, 3d4 at level 7 and 4d4 at level 9).