Umbral Scourge

You point at a creature, targeting it. Black tentacles emerge from a point on that creature, slowly growing out of it and siphoning its life. The target must make a DC charisma save.
On a failed save the creature initially takes 3d4 necrotic damage and at the end of its turns takes 1d4 necrotic damage, or only the initial damage on a successful one. You gain 1d4 temporary hitpoints whenever Umbral Scourge deals damage.

The tentacles disappear when you stop concentrating on the spell or by a remove curse spell cast at the same level as Umbral Scourge.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage (both initial and later) increases by 1d4 for each slot level above 2nd.