Traits
Amphibious: The dragon turtle can breathe air and also water.
Actions
Multiattack: This dragon turtle can make three attacks: one with its bite and two with its claws. It can make one tail Attack in place of its two claw attacks.
Bite: Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 (3d12 + 7) piercing damage.
Claw: Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 16 (2d8 + 7) slashing damage.
Tail: Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 (3d12 + 7) bludgeoning damage. Suppose, if the target was a creature, it should succeed on a DC 20 Strength saving throw or it should be pushed up to 10 feet away from the dragon turtle and knocked prone.
Steam Breath (Recharge 5-6): This dragon turtle would exhales scalding steam within a 60-foot cone. Each and every creature in that specific area should make a DC 18 Constitution saving throw and also taking 52 (15d6) fire damage on a failed save, or even half as much damage on a successful one. Even though being Underwater doesn’t grant Resistance against this damage.
Do you know that d&d 5e gargoyle monster is having some useful attributes, those are helpful to you.
Attributes
| AC | 
 20 (Natural Armor) 
 | 
| Alignment | Neutral | 
| CHA | 12 | 
| CON | 20 | 
| 
 Challenge Rating 
 | 
17 | 
| DEX | 10 | 
| HP | 
 341 (22d20+10) 
 | 
| INT | 10 | 
| Languages | Aquan, Draconic | 
| 
 Passive Perception 
 | 
11 | 
| Resistances | Fire | 
| 
 Roll 0 
 | 
 Bite 1d20 + 13 3d12+7 
 | 
| 
 Roll 1 
 | 
 Claw 1d20 + 13 2d8+7 
 | 
| 
 Roll 2 
 | 
 Tail 1d20 + 13 3d12+7 
 | 
| 
 Roll 3 
 | 
 Steam Breath 1d20 + 0 15d6 
 | 
| STR | 25 | 
| Saving Throws | 
 Dex +6, Con +11, Wis +7 
 | 
| Senses | 
 Darkvision 120 Ft. 
 | 
| Size | Gargantuan | 
| Speed | 
 20 ft., swim 40 ft. 
 | 
| Type | 
 dragon 
 | 
| WIS | 12 |