Dragon Turtle
gargantuan dragon, neutral
AC 20 (natural armor)
Initiative +0 (10)
HP 356 (23d20 + 115)
Speed 20 ft., Swim 50 ft.
Resistances fire
Senses Darkvision 120 ft. Passive Perception 11
Languages Draconic, primordial (aquan)
CR 17 (XP 18,000; PB +6)
Traits
Amphibious. The dragon can breathe air and water.
Actions
Bite. Melee Attack Roll: +13, reach 15 ft. Hit: 23 (3d10 + 7) Piercing damage plus 7 (2d6) Fire damage. Being underwater doesn't grant Resistance to this Fire damage.
Multiattack. The dragon makes three Bite attacks. It can replace one attack with a Tail attack.
Steam Breath (Recharge 5-6). Constitution Saving Throw: DC 19, each creature in a 60-foot Cone. Failure: 56 (16d6) Fire damage. Success: Half damage. Failure or Success: Being underwater doesn't grant Resistance to this Fire damage.
Tail. Melee Attack Roll: +13, reach 15 ft. Hit: 18 (2d10 + 7) Bludgeoning damage. If the target is a Huge or smaller creature, it has the Prone condition.
Dragon Turtle is from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, used under the Creative Commons Attribution 4.0 International License. Full attribution is on the Licenses & Attribution page.