- Armor Class 20 (natural armor)
- Hit Points 356 ()
- Speed 20 ft., swim 50 ft.
- Initiative +6 (16)
- Saving Throws ,
- Resistances fire
- Senses Darkvision 120 ft., Passive Perception 11
- Languages Draconic, Primordial (Aquan)
- Challenge 17 (18,000 XP; PB +6)
Traits
Amphibious. The dragon can breathe air and water.
Actions
Multiattack. The dragon makes three Bite attacks. It can replace one attack with a Tail attack.
Bite. Melee Attack Roll: , reach 15 ft. Hit: 23 () Piercing damage plus 7 () Fire damage. Being underwater doesn’t grant Resistance to this Fire damage.
Tail. Melee Attack Roll: , reach 15 ft. Hit: 18 () Bludgeoning damage. If the target is a Huge or smaller creature, it has the Prone condition.
Steam Breath (Recharge 5–6). Constitution Saving Throw: DC 19, each creature in a 60-foot Cone. Failure: 56 () Fire damage. Success: Half damage. Failure or Success: Being underwater doesn’t grant Resistance to this Fire damage.