Shambling Mound (CR 6)

Large Plant
Alignment: Always neutral
Initiative: +0; Senses: darkvision 60 ft. and Listen +8

AC: 20 (-1 size, +11 natural), touch 9, flat-footed 20
Hit Dice: 8d8+24 (60 hp)
Fort +9, Ref +2, Will +4
Speed: 20 ft.
Space: 10 ft./10 ft.
Base Attack +6; Grapple +15
Attack: Slam +11 melee
Full Attack: 2 slams +11 melee
Damage: Slam 2d6+7
Special Attacks/Actions: Improved grab, constrict 2d6+7
Abilities: Str 21, Dex 10, Con 17, Int 7, Wis 10, Cha 9
Special Qualities: electricity immunity, Plant, fire resistance 10
Feats: Iron Will; Power Attack; Weapon Focus (slam)
Skills: Hide +3*, Listen +8, and Move Silently +8
Advancement: 9-12 HD (Large); 13-24 HD (Huge)
Climate/Terrain: Temperate marsh
Organization: Solitary
Treasure: 1/10th coins; 50% goods; 50% items

Source: Monster Manual

Shambling mounds, or shamblers, appear to be heaps of rotting vegetation. They are actually intelligent plants, with a roughly humanoid shape and a brain-like control center in the "chest."

The carnivorous shambler is almost totally silent and invisible in its natural surroundings, often catching opponents flat-footed. It may lie partially submerged in a shallow bog, waiting patiently for some creature to walk. onto it. Shamblers move easily through water as well, and they have been known to sneak into the camps of unsuspecting travelers at night.

Adventurers tell stories of shamblers moving about during intense electrical storms without so much as flinching from direct lightning strikes.

A shambler's lower half has an 8-foot girth, tapering to about 2 feet at its "head."