Golem, Diamond (CR 12)

Large Construct
Alignment: Always neutral
Initiative: +1 (Dex); Senses: darkvision 60 ft.
Languages: Cannot speak

AC: 29 (-1 size, +1 Dex, +19 natural), touch 10, flat-footed 28
Hit Dice: 14d10+30 (107 hp); DR: 15/adamantine
Fort +4, Ref +5, Will +5
Speed: 30 ft. (cannot run)
Space: 10 ft./10 ft.
Base Attack +10; Grapple +24
Attack: 2 slams +19 melee
Full Attack: 2 slams +19 melee
Damage: Slam 2d6+10
Special Attacks/Actions: Spell-like abilities
Abilities: Str 31, Dex 12, Con -, Int 10, Wis 12, Cha 1
Special Qualities: Magic immunity, construct, ki vulnerability
Feats: Awesome Blow; Cleave; Improved Bull Rush; Improved Sunder; Power Attack
Skills: Climb +27 and Jump +27
Advancement: 15-28 HD (Large); 29-42 HD (huge)
Climate/Terrain: Any land and underground
Organization: Solitary, pair or troop (3-5)
Treasure/Possessions: None (except heart)

Source: Monster Compendium: Monsters of Faerûn

Targeted Dispel (Su): Any creature struck in melee combat by the diamond golem's fist is struck by a targeted dispel magic effect that operates as if it had been cast by a 16th-level wizard.

Spell-Like Abilities: A diamond golem may cast the sunbeam spell 1d3 times per day as if it were a 15th-level druid (five beams, one per round). At will, a diamond golem may cast true strike.

Magic Immunity (Ex): Diamond golems are immune to all spells, spell-like abilities and supernatural effects except as follows: A shatter spell affects the diamond golem per the spell's standard effects as does imprisonment. A mending spell heals all of the golem's damage.

Construct: Immune to mind-influencing effects, poison, disease, and similar effects. Not subject to critical hits, subdual damage, ability damage, energy drain, or death from massive damage.

Ki Vulnerability (Ex): Diamond golems can be struck and damaged by any character who possesses the ki strike ability, which monks gain at 10th level. Ki strike +1 is enough to damage the diamond golem. Any ki strike attack inflicts 1d6 damage for every point of ki strike the attacker possesses; for example, a 17th-level monk with ki strike +3 inflicts +3d6 damage on the diamond golem with each of her unarmed strikes.

Diamond golems use their sunbeam ability before entering serious combat. Due to their perfectionist obsession, diamond golems cast true strike before each of their melee attacks, even if doing so makes no tactical or strategic sense. They cannot attack in the round that they use the spell-like ability to cast true strike, and they only make one attack on rounds when they do strike. The exception to this rule is that diamond golems will make opportunity attacks.