Protean Scourge Arcanist (CR 16)

Medium Monstrous Humanoid (Shapechanger)
Alignment: Always neutral evil
Initiative: +9 (+5 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., Spot +13, and listen +13

AC: 25 (+5 Dex, +10 natural), touch 15, flat-footed 20
Hit Dice: 13d8+65 plus 4d4+20 (153 hp); DR: 10/silver
Fort +10, Ref +16, Will +16
Speed: 40 ft., climb 10 ft.
Space: 5 ft./5 ft.
Base Attack +15; Grapple +21
Attack: Claw +21 melee or scythe +21 melee
Full Attack: 2 claws +21 melee and gore +19 melee; or scythe +21/+16/+11 melee and gore +19 melee
Damage: Attack: Claw 2d6+6 or Powerful Charge 2d6+6 plus 1d8, scythe 2d4+9/x4 or Powerful Charge 2d4+7/x4 plus 1d8; Full attack: claw 2d6+6, gore 1d8+3, scythe 2d4+9/x4
Special Attacks/Actions: Spells, split
Abilities: Str 22, Dex 20, Con 21, Int 12, Wis 14, Cha 24
Special Qualities: Change shape, immunity to petrification and poison, resistance to cold 10 and electricity 10, SR 24, 4th-level Sorcerer
Feats: Improved Initiative; Improved Natural Attack (claws); Iron Will; Lightning Reflexes; Multiattack; Powerful Charge; Silent Spell
Skills: Bluff +20, Climb +14, Concentration +25, Diplomacy +9, Disguise +11 (+13 acting)*, Escape Artist +12, Gather Information +10, Intimidate +17, Sense Motive +5, Spot +13, Use Rope +5 (+7 with bindings), and listen +13
Advancement: By character class
Climate/Terrain: Temperate plains
Organization: Solitary
Treasure/Possessions: Standard

Source: Monster Manual III

A protean scourge arcanist casts various spells on itself before entering combat, starting with displacement, haste, and greater invisibility ability. Its tactics otherwise mirror those of an ordinary protean scourge.

Spells: A protean scourge sorcerer has access to more powerful magic, casting spells as a 12th-level sorcerer.

Typical Sorcerer Spells Known (6/8/8/8/7/6/4): 0 - acid splash (+20 ranged touch), dancing lights, daze (DC 17), detect magic, ghost sound (DC 17), mage hand, open/close, prestidigitation, read magic; 1st - charm person (DC 18), color spray (DC 18), mage armor, ray of enfeeblement (+20 ranged touch), ventriloquism (DC 18); 2nd - ghoul touch (+21 melee touch, DC 19), mirror image, scorching ray (+20 ranged touch), spider climb, spectral hand; 3rd - displacement, haste, suggestion (DC 20), vampiric touch (+21 melee touch); 4th - confusion (DC 21), enervation (+20 ranged touch), greater invisibility; 5th - baleful polymorph (DC 22), dominate person (DC 22); 6th - disintegrate (+20 ranged touch, DC 22).

Shapechanger Subtype

A shapechanger has the supernatural ability to assume one or more alternate forms. Many magical effects allow some kind of shape shifting, and not every creature that can change shapes has the shapechanger subtype.

Traits: A shapechanger possesses the following traits (unless otherwise noted in a creature's entry).