Amphibious. The leviathan can breathe air and water.
Multiattack. The leviathan makes three attacks: one with its tusks and two butt attacks. It can make one slam attack in place of its two butt attacks. Tusks. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 3d12+7 piercing damage. Butt. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 16 2d8+7 bludgeoning damage. Slam. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 3d12+7 bludgeoning damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be pushed up to 10 feet away from the leviathan and knocked prone. Blow Steam (Recharge 5–6). The leviathan blows scalding steam out of its trunk in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 52 15d6 fire damage on a failed save, or half as much damage on a successful one. Being underwater doesn't grant resistance against this damage.
Leviathans are massive and solitary, but usually nonthreatening beasts of the deep. They resemble a strange combination of a whale and an aquatic mammoth, with tusks, a short trunk, and webbed feet. Most leviathans spend the majority of their lives in the ocean depths, only coming closer to the surface or onto the shore to breed or give birth. However, the more sociable leviathans may offer help to other creatures, some even entering into partnerships with civilizations in need of long-distance oceanic transport. But leviathans are far from always benevolent, and an enraged leviathan can wipe a coastal town off the map, or even a small port city.
Coastal, Underwater