Bronze Serpent (CR 10)

Huge Construct
Alignment: Always neutral
Initiative: +9 (Dex)
Languages: Cannot speak

AC: 26 (-2 size, +9 Dex, +9 natural), touch 17, flat-footed 17
Hit Dice: 16d10+40 (128 hp); DR: 10/adamantine
Fort +5, Ref +14, Will +6
Speed: 50 ft., burrow 30 ft., climb 20 ft.
Space: 15 ft./10 ft.
Base Attack +12; Grapple +27
Attack: Bite +17 melee
Full Attack: Bite +17 melee
Damage: Bite 1d6+10 plus electricity
Special Attacks/Actions: Constrict 2d8+10, improved grab, shocking bite
Abilities: Str 25, Dex 28, Con -, Int -, Wis 13, Cha 3
Special Qualities: Construct traits, electric healing, electricity immunity, SR 21
Feats: -
Skills: Climb +15
Advancement: 17-32 HD (Huge); 33-48 HD (Gargantuan)
Climate/Terrain: Any land and underground
Organization: Solitary, pair, or cluster (3-5)
Treasure/Possessions: None

Source: Monster Manual II

Constrict (Ex): With a successful grapple check, a bronze serpent can crush a grabbed opponent, dealing 2d8+10 points of bludgeoning damage.

Improved Grab (Ex): If a bronze serpent hits an opponent that is at least one size category smaller than itself with a bite attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +27). If it gets a hold, it can also constrict in the same round. Thereafter, the creature has the option to conduct the grapple normally, or simply use its jaws to hold the opponent (-20 penalty on grapple check, but the bronze serpent is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals bite and constrict damage.

Shocking Bite (Su): A bronze serpent's bite deals 1d8+16 points of electricity damage in addition to the normal bite damage. The creature receives a +3 bonus on attack rolls against any opponent that is made out of metal, wearing metal armor, or carrying a significant amount of metal.

Construct Traits: A bronze serpent is immune to mind affecting effects, poison, sleep, paralysis, stunning, disease death effects, necromantic effects, and any effect that requires a Fortitude save unless it also works on objects. The creature is not subject to critical hits, subdual damage, ability damage, ability drain, energy drain, or death from massive damage. Is cannot heal itself but can be healed through repair or through its electric healing ability. It cannot be raised or resurrected. A bronze serpent has darkvision (60-foot range).

Electric Healing (Ex): Because of the bronze serpent's electrical affinity, any electricity attack directed at it cures 1 point of damage for each 3 points of damage it would other wise deal. The creature gets no saving throw against electricity effects.

A bronze serpent usually concentrates its initial attacks on the creatures that appear most vulnerable to its shocking bite. Once it hits with that attack, it wraps its body around the opponent, then continues biting while it constricts.