Blood Frenzy. The Zernid has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Nimble Escape. The Zernid can take the Disengage action as a bonus action on each of its turns.

Pack Tactics. The Zernid has advantage on an attack roll against a creature if at least one of the Zernid's allies is within 5 feet of it and the ally isn't incapacitated.

 Multiattack. The Zernid makes two attacks: one with its bite and one with its stinger. It can use its claws in place of one other attack.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage plus 3 (1d6) acid damage. If the target is a Medium or smaller creature, it is grappled (escape DC 15). Until this grapple ends, the Zernid can attack only the grappled creature and has advantage on attack rolls to do so.

Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 2) slashing damage.

Stinger. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 11 (2d6 + 4) piercing damage. The target must make a DC 15 Constitution saving throw, taking 3d6 acid damage on a failed save, or half as much damage on a successful one.