Slaughterstone Behemoth (CR 15)
Huge Construct (Earth)
Alignment: Always neutral
Languages: Cannot speak
AC: 36 (-2 size, +28 natural), touch 8, flat-footed 36
Hit Dice: 29d10+40 (199 hp); DR: 10/adamantine
Fort +9, Ref +9, Will +9
Speed: 20 ft.
Space: 15 ft./10 ft.
Base Attack +21; Grapple +42
Attack: Slam +32 melee
Full Attack: 4 slams +32 melee
Damage: Slam 4d6+13
Special Attacks/Actions: Dazing blow, thunder step, trample 4d6+19
Abilities: Str 37, Dex 11, Con -, Int -, Wis 10, Cha 1
Special Qualities: Construct traits, resistance to acid 10, cold 10, electricity 10, and fire 10, tunnel fighting, SR 23
Advancement: 30-45 HD (Huge)
Organization: Solitary or gang (2-4)
Monster Manual III
A slaughterstone behemoth approaches combat with the uncaring and brutal precision that most constructs exhibit. When confronted with large groups of foes, a behemoth wades into trample when appropriate and flails away with its limbs. Like its smaller counterpart, the slaughterstone eviscerator, a behemoth has no ranged combat capability and is at the mercy of highly mobile groups with powerful ranged attacks. For this reason, dwarves and other races that employ slaughterstone behemoths usually support them with powerful archers or spellcasters capable of striking down foes determined to fight from a distance.
Dazing Blow (Ex): Any creature struck by a slaughterstone behemoth must succeed on a DC 24 Fortitude save or be dazed for 1 round. The save DC is Wisdom-based.
Thunder Step (Ex): The ponderous steps of a slaughterstone behemoth shake the very earth. Any creature within 5 feet of a slaughterstone behemoth when it moves must succeed on a DC 24 Reflex save or fall prone. The save DC is Wisdom-based.
Trample (Ex): Reflex half DC 37. The save DC is Strength-based.
Tunnel Fighting (Ex): A slaughterstone behemoth has a limited ability to reshape its form to fit into a tight area. It does not take a penalty on attack rolls or to Armor Class when squeezing through a right space. See page 29 of the Dungeon Master's Guide for more information on squeezing through tight spaces.
This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Earth. Earth creatures usually have burrow speeds, and most earth creatures can burrow through solid rock.