Octopus Tree (CR 12)

Huge Plant
Alignment: Usually neutral evil
Initiative: +0; Senses: low-light vision, Listen +4, and Spot +14
Languages: understands Common, but lacks the body parts necessary for speech

AC: 28 (-2 size, -4 Dex, +24 natural), touch 4, flat-footed 28
Hit Dice: 14d8+70 (133 hp)
Fort +14, Ref +0, Will +6
Speed: 10 ft., swim 50 ft.
Space: 15 ft./15 ft.
Base Attack +10; Grapple +28
Attack: Tentacle +19 melee
Full Attack: 8 tentacles +19 melee and 1 bite +13 melee
Damage: Tentacle 2d6+10/19-20, bite 3d8+5
Special Attacks/Actions: Frightful presence, improved grab, spell-like abilities, swallow whole
Abilities: Str 30, Dex 3, Con 20, Int 8, Wis 15, Cha 15
Special Qualities: Acid immunity, plant traits, regeneration 10
Feats: Alertness; Improved Critical (tentacle); Improved Initiative; Quicken Spell-Like Ability; Weapon Focus (tentacle)
Skills: Listen +4, Spot +14, and Swim +25
Advancement: 15-35 HD (Gargantuan); 36-42 HD (Colossal)
Climate/Terrain: Temperate ocean surface
Organization: Solitary or grove (2-12)
Treasure/Possessions: Standard

Source: Fiend Folio

Octopus trees gain a fair amount of nourishment from photosynthesis, but without flesh, a tree ceases to grow in size. These plants often dwell near the fringes of busy shipping lanes; upon sighting a ship, they move quickly to intercept it, using magic if necessary. They use their tentacles to pluck food (passengers or crew) from the deck, eating one or two morsels quickly and holding anyone else they grab underwater so the victims drown. Octopus trees usually occupy areas with heavy seaweed growth so they can use their spell-like abilities to their full extent.

An octopus tree can be summoned using a summon nature's ally IX spell.

Frightful Presence (Ex): An octopus tree inspires terror in all creatures within 30 feet that have fewer Hit Dice or levels than it has. Each potentially affected opponent must succeed on a Will save (DC 19) or become shaken, a condition that lasts until the opponent is out of range. A successful save leaves that opponent immune to that octopus tree's frightful presence for one day.

Improved Grab (Ex): If an octopus tree hits an opponent that is at least one size category smaller than itself with a tentacle attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +28). If it gets a hold, it can transfer the opponent to its maw with another successful grapple check, dealing automatic bite damage. Alternatively, the octopus tree has the option to conduct the grapple normally or simply use its tentacle to hold the opponent (-20 penalty on grapple check, but the octopus tree is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals bite damage.

Spell-like Abilities: At will - diminish plants, entangle, obscuring mist, plant growth, warp wood; 3/day - call lightning, turn wood, wall of thorns. Caster level 14th; save DC 12 + spell level.

Swallow Whole (Ex): An octopus tree can swallow a single creature that is at least two size categories smaller than itself by making a successful grapple check (grapple bonus +28), provided it already has that opponent in its maw (see Improved Grab, above). Once inside the octopus tree, the opponent takes 2d6+9 points of bludgeoning damage and 2d4 points of acid damage per round from the plant's internal cavity. A successful grapple check allows the swallowed creature to climb out of the internal cavity and return to the octopus tree's maw, where another successful grapple check is needed to get free. Alternatively, a swallowed creature can try to cut its way our with either claws or a light piercing or slashing weapon. Dealing a total of at least 20 points of damage to the internal cavity (AC 22) in this way creates an opening large enough to permit escape. Once a single swallowed creature exits, rapid growth closes the hole; thus, another swallowed opponent must cut its own way out. An octopus tree's cavity can hold 1 Large, 4 Medium-size, or 16 Small or smaller opponents.

Regeneration (Ex): An octopus tree takes normal damage from fire and cold. Attack forms that don't deal hit point damage ignore regeneration, and an octopus tree does not restore hit points lost from starvation, thirst, or suffocation.

Skills: Octopus trees have a +8 racial bonus on any Swim check to perform some special action or avoid a hazard and can always choose to take 10 on Swim checks, even if distracted or endangered.