Living Catapult (CR 9)

Huge Construct
Alignment: Always neutral
Initiative: -1 (Dex)
Languages: Cannot speak

AC: 22 (-2 size, -1 Dex, +15 natural), touch 7, flat-footed 22
Hit Dice: 16d10 (88 hp); DR: 15/magic
Fort +5, Ref +4, Will +4
Speed: 20 ft.
Space: 20 ft./10 ft.
Base Attack +12; Grapple +16
Attack: Slam +20 melee; boulder +15 ranged
Full Attack: Slam +20 melee; boulder +15 ranged
Damage: Slam 2d6+15; boulder 5d6+10
Special Attacks/Actions: Launch boulder, Trample
Abilities: Str 30, Dex 8, Con -, Int -, Wis 9, Cha 10 (Ego: 1)
Special Qualities: Construct, magic immunity
Feats: -
Skills: -
Advancement: 17-32 (Gargantuan), 33-48 HD (Colossal)
Climate/Terrain: Any land
Organization: Solitary or gang (2-5)
Treasure/Possessions: None

Source: Dragon #285

Launch Boulder (Ex): As a standard action, a living catapult can pick up a boulder weighing 60 to 80 pounds (Medium-size object) with its launching arm and hurl it as a ranged weapon with a 200-foot range increment.

Trample (Ex): As a standard action during its turn each round, the creature can literally run over an opponent at least one size category smaller than itself. The trample deals 3d12+5 bludgeoning damage. A trampled opponent can either attempt attacks of opportunity at a -4 penalty or make a Reflex save (DC 28) for half 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.

Magic Immunity (Ex): Living catapults completely resist most magical and supernatural effects, except as follows: Warp wood or wood shape spells cause 2d8 points of damage and hold the living catapult immobile for 1 round. Fire effects cause damage normally.

Living catapults are normally set up to attack foes from afar but when enemies get too close, they attempt to run them down or smash them.