Bitter Ghast

Keen Smell. The ghast has advantage on Wisdom (Perception) check that rely on smell.

Stench. Any creature that starts its turn within 5 feet of the ghast must succeed on a DC 12 Constitution saving throw or be poisoned until the start of its next turn. On a successful saving throw, the creature is immune to the ghast's Stench for 24 hours.

Turning Rage. If the ghast succeeds on a saving throw against an effect that turns undead, it falls into a frenzy until the end of its next turn. While frenzied, the ghast has advantage on attack rolls and saving throws against being charmed or frightened and effects that turn undead.

Multiattack. The ghast makes two attacks: one with its bite, and one with its claws.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 6 (1d8 + 2) piercing damage.

Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) slashing damage. If the target is a creature other than an undead, it must succeed on a DC 12 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.