Greenvise (CR 10)

Huge Plant
Alignment: Always neutral
Initiative: +0; Senses: woodsense

AC: 16 (-2 size, +8 natural), touch 8, flat-footed 16
Hit Dice: 12d8+48 (102 hp)
Fort +12, Ref +4, Will +4
Speed: 10 ft.
Space: 15 ft./15 ft.
Base Attack +9; Grapple +26
Attack: Slam +16 melee
Full Attack: 4 slams +16 melee and bite +11 melee
Damage: Slam 2d4+9, bite 1d6+4
Special Attacks/Actions: Death fog, improved grab, swallow whole
Abilities: Str 29, Dex 10, Con 18, Int 3, Wis 11, Cha 6
Special Qualities: Acid immunity, plant traits
Feats: Cleave; Improved Initiative; Improved Critical (bite); Power Attack; Skill Focus (hide)
Skills: Hide +10
Advancement: 13-18 HD (Huge); 19-36 HD (Gargantuan)
Climate/Terrain: Temperate or warm hills, plains or marsh
Organization: Solitary, pair, or patch (3-8)
Treasure/Possessions: None

Source: Monster Manual II

Death Fog (Su): Twice per day, a greenvise can emit an acidic fog that functions like an acid fog spell except as follows: The death fog's area is a 40-foot high spread with a 60-foot radius. Within this area, all sight, including darkvision, is limited to 5 feet. A creature within 5 feet has one-half concealment (attacks against it have a 20% miss chance). Creatures farther away have total concealment (50% miss chance, and the attacker cannot use sight to locate the target). Any creature attempting to move through the death fog progresses at one-tenth normal speed, and each of its melee attack and melee damage rolls incurs a -2 circumstance penalty. A death fog prevents effective ranged weapon attacks, except for magic rays and the like.

In addition to obscuring sight, a death fog is highly acidic. Each round, the fog deals 3d8 points of acid damage to every creature and object within it (no saving throw). A severe wind (31+ mph) disperses these vapors in 1d2 rounds; otherwise, the effect lasts for 3d6+1 rounds. The greenvise is not impeded by its own death fog, so it can move and fight within the fog freely.

Improved Grab (Ex): If a greenvise hits an opponent that is at least one size category smaller than itself with a slam attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +26). If it gets a hold, it can transfer the opponent to its maw with another successful grapple check, dealing automatic bite damage, then try to swallow in the next round. Alternatively, the greenvise has the option to conduct the grapple normally, or simply use its tendrils or maw to hold the opponent (-20 penalty on grapple check, but the greenvise is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals slam or bite damage, as appropriate.

Swallow Whole (Ex): A greenvise can swallow a single creature that is at least one size category smaller than itself by making a successful grapple check (grapple bonus +26), provided it already has that opponent in its maw (see Improved Grab, above). Once inside the greenvise, the opponent takes 2d6+9 points of bludgeoning damage and 2d4 points of acid damage per round from the plant's stomach. A successful grapple check allows the swallowed creature to climb out of the stomach and return to the greenvise's maw, where another successful grapple check is needed to get free. Alternatively, a swallowed creature can try to cut its way out with either claws or a light piercing or slashing weapon. Dealing at least 20 points of damage to the stomach (AC 18) in this way creates an opening large enough to permit escape. Once a single swallowed creature exits, muscular action closes the hole; thus, another swallowed opponent must cut its own way out. A greenvise's stomach can hold 1 Large, 4 Medium-size, 16 Small, or 64 Tiny or smaller opponents.

Plant Traits (Ex): A greenvise is immune to poison, sleep, paralysis, stunning, and polymorphing. It is not subject to critical hits or mind-affecting effects. The creature also has low-light vision.

Woodsense (Ex): A greenvise can automatically sense the location of anything within 60 feet that is in contact with vegetation, even objects or creatures that are not in contact with the same vegetation as it is.

After setting itself up in an appropriate location, a greenvise lies in wait for prey to pass. It lunges at the first living creature it senses, using all its tendrils to grab the prey and transfer it to its maw. An extremely hungry or seriously hurt greenvise releases a death fog to weaken its opponents and obscure their vision. Although multiple greenvises are sometimes found together, they do not share their prey and they do not assist each other in combat unless many potential victims are present.