Stingers

Melee Weapon Attack: +8 to hit, reach 0 ft., one target in the swarm's space. Hit: 21 (6d6) piercing damage, or 10 (3d6) piercing damage if the swarm has half of its hp or fewer. The target must make a DC 16 Constitution saving throw. On a failure, a creature takes 42 (12d6) necrotic damage and is blinded for 1 minute. On a success, a creature takes half the damage and isn't blinded. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Douse Light

As the nyctli, except the swarm can't dispel light created by a spell of 6th level or higher.