Mimicing Cry. The Extallus can perfectly mimic the voice of a humanoid it has heard before. It takes a DC14 intelligence check to uncover that the voice is fake.
Swift. The Extallus does not provoke oppertunity attacks and can dash as a bonus action.
Blind. The Extallus cannot see.
Howling Screech 1/day. The Extallus lets out a screech so deafening that it succeeds a saving throw it previously failed. It becomes deafened for one turn.
Multiattack. The Extallus makes a bite attack and a claw attack.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage.
Claw. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 7 (1d6 + 4) slashing damage.
Haunting Cry. The Extallus lets out a haunting cry. Each creature of the Nucklavees choice within 20ft. of it must succeed on a DC 14 Wisdom saving throw taking 8 (3d4) psychic damage or half as much on a successful one.
Snappy Howl. The Nuckelavee screeches. Imposing disadvantage on an incoming melee attack.