Keen Smell. The Boo has advantage on Wisdom (Perception) checks that rely on smell.
Shadow stealth. when in dim light, the boo has advantage on stealth checks, and the boo receives a +10 bonus to stealth checks. While in darkness, the boo gains a +20 bonus to stealth checks, and has advantage on the roll.
Multiattack. The boo makes six attacks. two with her claws, one with her bite, one with her behind, casts a spell twice, and uses her enervation ray.
Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 1 slashing damage, plus 30 (5d8+5 ) necrotic damage, plus 19 (5d6+3) lightning damage.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 1 piecing damage, plus 30 (5d8+5 ) necrotic damage, plus 19 (5d6+3) lightning damage, plus 10 (3d6+1) acid damage.
Behind. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. the target must succeed on a DC 20 wisdom saving throw, taking 10 (3d6) psychic damage on a failed save, plus 30 (5d8+5 ) necrotic damage, plus 19 (5d6+3) lightning damage.
Enervation ray. The boo shoots negative energy at a creature she can see within 300 feet of her. the target must succeed on a DC 20 dexterity saving throw, taking 35 (10d6+5) necrotic damage on a successful save, and double as much as a failed save.
Enervation blast. The boo creates a one foot sphere of negative energy centered on a point she can see within 500 feet of her. The one foot sphere extends outward to a 30 foot sphere. Any creature within that sphere takes 150 (30d6+50) necrotic damage and 10 (2d10) lighting damage.