Night Twist (CR 12)

Large Plant
Alignment: Always neutral evil
Initiative: -2 (Dex); Senses: low-light vision, Listen +9, and Spot +12

AC: 27 (-1 size, -2 Dex, +15 natural, +5 deflection), touch 12, flat-footed 27
Hit Dice: 15d8+135 (202 hp); DR: 10/slashing
Fort +23, Ref +8, Will +14
Speed: 10 ft.
Space: 10 ft./20 ft.
Base Attack +11; Grapple +29
Attack: Slam +24 melee
Full Attack: 3 slams +24 melee
Damage: slam 2d8+14
Special Attacks/Actions: Death curse, despair song, spell-like abilities, wind blast
Abilities: Str 39, Dex 6, Con 29, Int 12, Wis 14, Cha 21
Special Qualities: plant traits, unholy grace, vulnerability to fire
Feats: Blind-fight; Diehard; Endurance; Improved Sunder; Iron Will; Power Attack
Skills: Hide +7, Knowledge (nature) +10, Listen +9, Move Silently +8, Spot +12, and Survival +9 (+11 aboveground)
Advancement: 16-24 HD (Large); 25-48 HD (Huge)
Climate/Terrain: Temperate marshes
Organization: Solitary
Treasure: Standard coins, no goods, standard items

Source: Monster Manual III

You see a large, black, leafless tree characterized by unnatural and unsettling shapes. It radiates gloomy twilight, nightmares, and sorrow.

Long before luckless travelers in more remote and foreboding marshes see the harrowing sight of a lone night twist, they hear its haunting and melancholy song. The ghostly moaning sounds of its song seem slightly different to every traveler. For some, the song of the night twist sounds like a women weeping. To others, it is more akin to a cold wind blowing over a desolate graveyard. Most likely, the despair song of a night twist is the most sorrowful sound each traveler can conjurer within his or her own mind.

Night twists subsist in the most inhospitable marshes, feeding on the rotting carcasses of creatures and travelers attracted by its despair song. A typical night twist stands 15 feet tall and weighs 600 pounds.

Night twists rarely speak, but they understand Common, Elven, and Sylvan.