Dire Tortoise (CR 8)

Huge Animal
Alignment: Always neutral
Initiative: -2 (Dex); Senses: low-light vision, Listen +6, and Spot +6

AC: 25 (-2 size, -2 Dex, +19 natural), touch 6, flat-footed 25
Hit Dice: 14d8+107 (170 hp)
Fort +16, Ref +7, Will +9
Speed: 20 ft., burrow 20 ft.
Space: 15 ft./10 ft.
Base Attack +10; Grapple +26
Attack: Bite +16 melee
Full Attack: Bite +16 melee
Damage: Bite 1d8+12
Special Attacks/Actions: Lightning strike, trample 4d8+12
Abilities: Str 26, Dex 6, Con 25, Int 2, Wis 10, Cha 6
Special Qualities:
Feats: Alertness; Endurance; Toughness (3)
Skills: Hide -1*, Listen +6, and Spot +6
Advancement: 15-28 HD (Huge); 29-42 HD (Gargantuan)
Climate/Terrain: Warm deserts
Organization: Solitary or pair
Treasure/Possessions: None

Source: Sandstorm

Lightning Strike (Ex): A dire tortoise can lash out very rapidly. On the first round of combat, it gets a surprise round regardless of whether it has been noticed. A creature that notices the dire tortoise is still treated as flat-footed during this round.

Trample (Ex): Reflex half DC 25. The save DC is Strength-based.

Skills: *A dire tortoise has a +12 racial bonus on Hide checks in rocky terrain.

Dire tortoises rely on their camouflage and protection. If approached, they lunge suddenly at any creature within reach of their powerful jaws.