Creature Codex (p.277)
Flyby. The nightgaunt doesn’t provoke an opportunity attack when it flies out of an enemy’s reach. Pack Tactics. The nightgaunt has advantage on attack rolls against a creature if at least one of the nightgaunt’s allies is within 5 feet of the creature and the ally isn’t incapacitated. Magic Resistance. The nightgaunt has advantage on saving throws against spells and other magical effects. Utterly Silent. The nightgaunt doesn’t make a sound and has advantage on Dexterity (Stealth) checks. Void Traveler. The nightgaunt doesn’t require air, food, drink, or ambient pressure.
Multiattack. The nightgaunt can use its Baneful Presence. It then makes three attacks: two with its clutching claws and one with its barbed tail. If the nightgaunt is grappling a creature, it can use its barbed tail one additional time. Clutching Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage, and the target is grappled (escape DC 16) if it is a Medium or smaller creature. Until this grapple ends, the target is restrained. The nightgaunt has two claws, each of which can grapple only one target. While using a claw to grapple, the nightgaunt can’t use that claw to attack. Barbed Tail. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage plus 10 (3d6) poison damage. Baneful Presence. Each creature of the nightgaunt’s choice that is within 30 feet of the nightgaunt and aware of it must succeed on a DC 16 Wisdom saving throw or have disadvantage on all attack rolls and saving throws for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the nightgaunt’s Baneful Presence for the next 24 hours.