Actions

Multiattack. The barrowghast makes two Slam attacks. It can replace one Slam attack with a Life Drain attack.   Slam. Melee Weapon Attack: +8 to hit, reach 2 sq., one target. Hit: 18 ( 2d12+5 ) bludgeoning damage.   Life Drain. Melee Weapon Attack: +8 to hit, reach 2 sq., one creature. Hit: 9 ( 1d8+5 ) necrotic damage, and the target must succeed on a DC 16 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. A Humanoid slain by this attack immediately rises as a Zombie (see the Monster Manual). The zombie acts as an ally of the barrowghast but isn't under its control.

Reactions

Noxious Wound. Immediately after the barrowghast takes piercing or slashing damage, poisonous ichor sprays from the wound. Each creature within 1 square of the barrowghast must make a DC 16 Dexterity saving throw, taking 10 ( 3d6 ) poison damage on a failed save, or half as much damage on a successful one.