Leviathan

The leviathan is an immense sea creature that takes up residence in a stretch of water, usually a very deep strait, and terrorizes shipping through that zone for years. It sinks some ships and lets others pass without interference, according to its own unfathomable whims. Decades may pass without a sighting; then, for no apparent reason, the attacks resume, usually in a new location. Whether this is the same beast awakened from hibernation, the same beast somehow reborn, or an entirely new creature is unknown.

The leviathan is an immense whale of almost unimaginable proportions. Some have seen its head, others have seen its tail, but those who have seen enough of the monster to determine its actual size and appearance are dead.

Wherever the leviathan goes, other sea predators follow, because a sinking ship produces a rich feeding ground for sharks, barracudas, many varieties of giant fish, dark rays, and even sahuagin and locathah. Although the leviathan itself has no interest in treasure, the sea bed beneath its hunting ground becomes a graveyard for the contents of sunken ships. Many of these hulks are laden with treasure and valuable cargo.

Combat

Obviously, a creature such as the leviathan has no natural enemies. Everything in the ocean is its prey, but ships seem to be the only things that catch its attention. Once it breaches or swamps a ship, the leviathan circles back and begins scooping the bodies of both the living and the dead into its 20-footwide mouth. Its tactics imply a level of anger and a desire to spread destruction that contradict its low Intelligence score.

Gulp (Ex): A leviathan can swallow a Huge or smaller creature by making a successful bite attack. The monster’s interior contains a mass of surging water. Each swallowed creature must make a Swim check (DC 15) every round. Success means the swallowed creature takes 1d3 points of subdual damage but can attack the leviathan from inside with any weapon other than a bow or crossbow. Failure means the swallowed creature takes 1d6 points of subdual damage and must immediately make a second Swim check (DC 15) to avoid going underwater and starting to drown. Anyone attacking the leviathan from the inside hits automatically. If the leviathan takes 50 points of damage from the inside, it disgorges the entire contents of its stomach.

Ramming (Ex): Once every 12 rounds, a leviathan can move at up to 720 feet and ram a Large or smaller creature or any sort of ship. To ram, the leviathan must end its movement in the target’s space. If the target is a ship, the creature always precedes this attack with a long surface approach so everyone aboard can see what’s coming. This attack deals 8d6+22 points of damage. If the target is a creature, it can attempt either an attack of opportunity or a Reflex save (DC 31) for half damage.

Upon ramming a ship, the leviathan can make a Strength check to breach its hull, which causes it to sink in 1d10 minutes. The break DC varies with the type of vessel rammed, as follows: rowboat DC 20, keelboat DC 23, sailing ship or longship DC 25, warship DC 27, or galley DC 30. (See Transport or Vessels for information about ships.) Regardless of the check result, every creature aboard must attempt a Reflex saving throw (DC 15). Success means the creature takes 1d10 points of damage from being thrown about by the impact; failure means the creature is hurled overboard.

Swamping (Ex): Once every 12 rounds, a leviathan can create waves up to 40 feet high by rising from the water and then slamming its enormous tail flukes or head against the surface. This causes any sailing vessel within 300 feet to capsize if the character steering it fails a Profession (sailor) check (DC 15). A modifier applies to this check based on the type of ship, as follows: rowboat –⁠2, warship +0, galley or keelboat +3, sailing ship +5, longship +7. Any creature flung into the water by a capsizing ship must succeed at a Swim check (DC 15) or immediately begin drowning.

Source: Monster Manual II, page 139. This creature’s statistics block has been updated to version 3.5 as given in the D&D® V.3.5 Accessory Update for Monster Manual II. The latter publication failed to update the creature’s space/reach, so the figure given is an estimate at best. Chapter 5 of the Dungeon Master’s Guide does not, as stated in the original text under Ramming, have any information about ships,