Shambling Mound, Serpentine (CR )

Large Plant
Alignment: Chaotic Neutral
Initiative: +2 (Dex); Senses: darkvision 60 ft. and Listen +8

AC: 20 (-1 size, +2 Dex, +9 natural), 9 touch, flat-footed 18
Hit Dice: 11d8+33 (115 hp)
Fort +9, Ref +2, Will +4
Speed: 30 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, fire immunity, Plant, half damage from cold (no damage on Fort save). Half damage blunt or slashing weapons, regeneration, lightning attacks add 1 foot in length and 1d8 hp.
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

Source: Converted

Serpentine shambling mounds started out as regular shambling mounds that were contaminated by vile magic. This magic resulted in an elongation of their bodies until they resembled immense serpents, head and hands on one end, legs on the other.