Armor Class 18 (natural armor)
Hit Points 90 (12d10 + 24)
Speed 20 ft., swim 30 ft.
Saving Throws DEX +2, CON +4, WIS +2
Damage Resistances fire
Senses darkvision 120 ft., passive Perception 10
Languages Draconic
Challenge 4
Amphibious. The dragon turtle can breathe air and water.
Bite. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 11 (1d12 + 3) piercing damage.
Steam Breath (Recharge 5–6). The dragon turtle exhales steam in a 15-foot cone. Each creature in that area must make a DC 12 Constitution saving throw, taking 17 (5d6) fire damage on a failed save, or half as much damage on a successful one. Being underwater doesn't grant resistance against this damage.
Fizban's Treasury of Dragons, p. 192