Platnumatl

Platnumatl CR 9

XP 6,400
N Small magical beast
Init +8; Senses darkvision 60 ft., tremorsense 60 ft.; Perception +13

AC 23, touch 15, flat-footed 19 (+4 Dex, +8 natural, +1 size)
hp 114 (12d10+48)
Fort +14, Ref +12, Will +7
Defensive Abilities freedom of movement; DR 10/adamantine; Immune disease, poison; Resist fire 10

Speed 30 ft., climb 30 ft.
Melee 2 bites +18 (1d6+5 plus 2d6 acid)

Str 21, Dex 18, Con 18, Int 2, Wis 13, Cha 11
Base Atk +12; CMB +16 (+20 grapple); CMD 30 (can’t be tripped)
Feats Bleeding Critical, Critical Focus, Great Fortitude, Improved Initiative, Iron Will, Skill Focus (Perception)
Skills Climb +13, Perception +13, Stealth +17 (+25 when gaining cover from metal objects); Racial Modifiers +8 Stealth when hiding behind cover provided by metal objects
SQ swift strike

Environment temperate plains, hills, or forests
Organization solitary, pair, or clutch (3–12)
Treasure standard

Freedom of Movement (Ex) A platnumatl benefits from a continuous freedom of movement effect, as per the spell of the same name. This effect cannot be dispelled.
Swift Strike (Ex) When a platinum serpent takes a full-attack action, it can make two bite attacks instead of just one.