Blacklight Web

You conjure a pulse of black light from a focal point. A black web of light bursts into a 30-foot cube and attempts to ensnare anyone within it.

Each creature within the burst radius must make a Dexterity saving throw. On a failed save, the creature is restrained as long as it remains in the webs or until it breaks free.

A creature restrained by the webs can use its action to make a Strength check against your spell save DC. If it succeeds, it is no longer restrained.

The webs are made of necrotic energies dealing 2d4 Necrotic damage to any creature that starts its turn restrained by them.