Clasp of Shadows

One Creature you can see that is in total darkness or touching its shadow must make a strength saving throw or be restrained. A creature may use its action or spend all its movement to repeat the saving throw. On a Successful saving throw the spell ends.

Alternatively if the Spell crosses into an area with magical bright light from a spell of 2nd level or greater the spell ends. 

Once on each of your turns you may use a bonus action to deal 1d8 necrotic damage to each affected creature.

Using a Higher-Level Spell Slot. You can target one additional creature for each spell slot level about 1.