Vassal's Life Drain

You drain the life energy of a small  area and anything in it, centered at a point you can see within range. Each creature in a 10-foot-radius sphere centered on that point must make a Constitution saving throw. A creature takes 2d8 necrotic damage on a failed save, or half as much damage on a successful one. For every creature that is caught inside the draining area, you regain 1 Hit Point.

This spell effects all things that derive from organic matter, making organic non creatures things wither to some extent. 

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 and the healing increases by 1 for each slot level above 2nd.