This enormous troll body has a little gnome growing where its head should be.
CR 12; XP 19,200
NE Huge Monstrous Humanoid
Init +7; Senses darkvision 120-ft., low-light vision, scent; Perception +27
AC 27, touch 11, flat-footed 24 (+3 Dex, +16 natural, –2 size)
hp 157 (15d10+75); regeneration 15 (acid, cold iron, fire)
Fort +12, Ref +14, Will +14
Defensive Abilities rock catching; DR 10/cold iron
Speed 40 ft.
Melee 2 claws +24 (3d6+10/19–20)
Ranged thrown rock +16 (2d8+15)
Special Attacks rock throwing (100 ft.), wicked tricks
Str 30, Dex 16, Con 20, Int 21, Wis 21, Cha 21
Base Atk +15; CMB +27; CMD 40
Feats Alertness, Combat Reflexes, Great Fortitude, Improved Critical (claw), Improved Initiative, Lightning Reflexes, Power Attack, Weapon Focus (claw)
Skills Appraise +20, Bluff +20, Intimidate +23, Knowledge (arcana) +20, Knowledge (nature) +20, Perception +27, Profession (gourmet) +20, Sense Motive +24, Survival +23
Language Common, Giant, Gnome, Sylvan
Environment temperate forests and mountains
Wicked Tricks (Sp) A shrewdhead's gnome part wields fey magics that it can use as a swift action three times per day, producing one of the following effects: baleful polymorph, blindness/deafness, confusion (single target), greater dispel magic, or telekinesis. All the effects are heightened to 6th level and have saving throw DC of 21.
According to a legend, the first shrewdhead was created by a bored fey lord by stitching a gnome to a troll, in place of its head. The troll's preternatural vitality sustained the new creation with the gnome's wits taking over the creature, twisted by pain, rage, and madness into a malice toward fey and mortal alike. Other legends say that the first shrewdhead was a gnome who sewed oneself on a troll body to ascend to a minor fey lord but was banished from the Otherworld into the lands of the mortal, retaining wicked intent and some lesser fey magics.
Currently living generation of shrewdheads is a bunch of solitary, selfish, malicious creatures, occasionally taking lead of lesser giants and trolls. While they lack voracity of actual trolls, they are exceptionally cunning and enjoy tormenting mortals and fey, they are not above eating them given the chance, but always carefully prepared into a fancy meal, never raw.