Multiattack

The dragon can use its Oil Spray. It then makes three attacks: one with its bite and two with its fists.

Bite

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 3 (1d6) fire damage.

Fist

Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) bludgeoning damage.

Fire Breath (Recharge 6)

The dragon exhales fire in a 30-foot cone. Each creature in that area must make a DC 16 Dexterity saving throw, taking 35 (10d6) fire damage on a failed save, or half as much damage on a successful one.

Oil Spray

The dragon sprays oil in a 30-foot-cone. Each creature in the area must succeed on a DC 16 Dexterity saving throw or become vulnerable to fire damage until the end of the dragon's next turn.

Tail Sweep

The dragon swings its bladed tail. Each creature within 10 feet of the dragon must make a DC 17 Dexterity saving throw, taking 15 (2d8 + 6) slashing damage on a failed save, or half as much damage on a successful one.