Black Weredragon

Shapechanger. The weredragon can use its action to polymorph back into its true form, which is humanoid. The weredragon reverts to its humanoid form if it dies.

Multiattack: The Black Weredragon can take as many attacks as it could in its humanoid form using the same weapon or from the following:

Bite. Melee Weapon Attack: +6 + prof to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 4 (1d8) acid damage. If the target is humanoid they must make a DC 12 consitution saving throw or be cursed with dragon lycanthropy.

Claw. Melee Weapon Attack: +6 + prof to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Frightful Presence. One creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened 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 Black Weredragon's Frightful Presence for the next 24 hours.

Breath Attack (Recharge 5-6,). The Black Weredragon exhales a 30-foot line that is 5 feet wide of green burning acid. Each creature in that area must make a DC 15 Dexterity saving throw, taking 18 (4d8) acid damage on a failed save, or half as much damage on a successful one.

Tail. Melee Weapon Attack: +6 + prof to hit, reach 15 ft., one target. Hit: 11 (1d8 + 6) bludgeoning damage.