Giant, Ocean (CR 19)

Huge Giant (Cold and Aquatic)
Alignment: Usually good
Initiative: +6 (+2 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., Listen +16, and Spot +16

AC: 26 (-2 size, +2 Dex, +16 natural), touch 10, flat-footed 24
Hit Dice: 18d8+162 (243 hp)
Fort +20, Ref +8, Will +8
Speed: 40 ft., swim 80 ft.
Space: 15 ft./15 ft.
Base Attack +13; Grapple +35
Attack: Two-handed trident +25 melee and tail slap +20 melee, or 2 slams +25 melee and tail slap +20 melee, or rock +14 ranged
Full Attack: Two-handed trident +25/+20/+15 melee and tail slap +20 melee, or 2 slams +25 melee and tail slap +20 melee, or rock +14 ranged
Damage: Two-handed trident 4d6+21, slam 1d6+14, tail slap 1d10+7, rock 2d8+14
Special Attacks/Actions: Rock throwing
Abilities: Str 39, Dex 15, Con 28, Int 11, Wis 14, Cha 18
Special Qualities: Amphibious, blunt weapon immunity, cold subtype, landform, rock catching
Feats: Combat Reflexes; Endurance; Far Shot; Improved Initiative; Point Blank Shot; Precise Shot; Shot on the Run
Skills: Diplomacy +6, Listen +16, Sense Motive +16, Spot +16, and Swim +22
Advancement: By character class
Climate/Terrain: Any aquatic
Organization: Solitary, pair, or family (3-8 plus 1-4 noncombatants plus 1 7th-10th level cleric or sorcerer and 2-8 sea lions)
Treasure/Possessions: Double standard

Source: Monster Manual II

Rock Throwing (Ex): An adult giant is an accomplished rock thrower, so he or she receives a +1 racial bonus on attack rolls when throwing rocks. A giant of at least Huge size can hurl rocks weighing 60 to 80 pounds each (Medium-size objects) up to five range increments (range increment 120 feet).

Rock catching (Ex): A giant of at least Huge size can catch Small, Medium-size, Large, or Huge rocks (or projectiles of similar shape). A Colossal giant can catch rocks of up to Colossal size. Once per round, a giant that would normally be hit by a rock can make a Reflex save to catch it as a free action. The DC to catch a rock is based on the rock's size (see table below). If the projectile has a bonus on attack rolls because of magic, the DC increases by that amount. The giant must be ready for and aware of the attack.

Rock SizeDC
Medium-size 20

Amphibious (Ex): Although ocean giants have gills for breathing underwater, they can also breathe air and can survive indefinitely on land.

Blunt Weapon Immunity (Ex): An ocean giant takes no damage from bludgeoning weapons.

Cold Subtype (Ex): An ocean giant is immune to cold damage but takes double damage from fire unless a saving throw for half damage is allowed. In that case, the giant takes half damage on a success and double damage on a failure.

Landform (Su): This ability allows an ocean giant to assume the form of a Huge humanoid-shaped giant or return to its natural form at will. An ocean giant in landform is able to walk on land, but it has no tail attack. A change wrought by landform cannot be dispelled, nor does the ocean giant revert to its natural form when killed. A true seeing spell, however, reveals the ocean giant's natural shape if it is in landform.

Cold Subtype

A creature with the cold subtype has immunity to cold. It has vulnerability to fire, which means it takes half again as much (+50%) damage as normal from fire, regardless of whether a saving throw is allowed, or if the save is a success or failure.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.