Barghest

This snarling, canine beast pads forward on all fours, its slender front limbs looking more like hands than a wolf’s paws.

Barghest CR 4

XP 1,200
LE Medium outsider (evil, extraplanar, lawful, shapechanger)
Init +6; Senses darkvision 60 ft., scent; Perception +11

AC 17, touch 12, flat-footed 15 (+2 Dex, +5 natural)
hp 45 (6d10+12)
Fort +6, Ref +7, Will +7
DR 5/magic

Speed 30 ft.
Melee bite +10 (1d6+4), 2 claws +10 (1d4+4)
Special Attacks feed
Spell-Like Abilities (CL 6th)

At will—blink, levitate, misdirection
1/day—charm monster (DC 16), crushing despair (DC 16), dimension door

Str 19, Dex 15, Con 15, Int 14, Wis 14, Cha 14
Base Atk +6; CMB +10; CMD 22 (24 vs. trip)
Feats Combat Reflexes, Improved Initiative, Great Fortitude
Skills Acrobatics +11, Bluff +11, Diplomacy +11, Intimidate +11, Perception +11, Sense Motive +11, Stealth +11, Survival +11
Languages Goblin, Infernal
SQ change shape (goblin or wolf, polymorph)

Feed (Su)

Once per month, a barghest can devour a nonevil humanoid’s corpse as a full-round action to gain a growth point. It gains a bonus equal to its growth point total on attack rolls, CMB rolls, saving throws, and skill checks. Its maximum hit points increase by 5 for each growth point it gains. For every 2 growth points, a barghest’s caster level for its spell-like abilities and its CR increase by +1. When a barghest reaches 4 growth points, it sheds its skin and becomes a greater barghest, losing all of its growth points (and bonuses) but gaining the stats presented on the page for a greater barghest.

Environment any
Organization solitary or cult (1 plus goblin tribe)
Treasure standard

Said to be fiendish relations of all goblinoid races, the hateful barghests come to the Material Plane to feed. As they consume the bodies of innocents, they grow increasingly powerful. A barghest eventually sheds its skin to transform into a greater barghest, at which point it often seeks out a tribe of goblins or other creatures to rule.