Indricothere (CR 9)

Huge Animal
Alignment: Always neutral
Initiative: +4; Senses: darkvision 60 ft., low-light vision, scent, Listen +14, and Spot +13

AC: 19 (-2 size, +11 natural), touch 8, flat-footed 19
Hit Dice: 16d8+112 (177 hp)
Fort +19, Ref +10, Will +7
Speed: 40 ft.
Space: 15 ft./10 ft.
Base Attack +12; Grapple +31
Attack: Head butt +22 melee
Full Attack: Head butt +22 melee and 2 stamps +16 melee
Damage: Head butt 2d6+11/19-20, stamps 2d6+5
Special Attacks/Actions: Knock back, trample 2d8+16
Abilities: Str 33, Dex 10, Con 25, Int 2, Wis 14, Cha 9
Special Qualities:
Feats: Alertness; Combat Reflexes; Great Fortitude; Improved Critical (head butt); Improved Initiative; Weapon Focus (head butt)
Skills: Listen +14 and Spot +13
Advancement: 17-31 HD (Gargantuan); 32-48 HD (Colossal)
Climate/Terrain: Any forest, hill, or plains
Organization: Solitary, pair, or herd (3-12)
Treasure/Possessions: -

Source: Fiend Folio

Knock Back (Ex): A creature hit by an indricothere's head butt attack must succeed on a Fortitude save (DC 29) or be knocked back 10 feet. If the target can't be knocked back 10 feet, it instead falls to the ground. If the first save fails, the target must succeed on another Fortirrsde save (DC 29) or be stunned for 1 round.

Trample (Ex): As a standard action, an indricothere can trample opponents at least one size category smaller than itself. This attack deals 2d8+16 points of bludgeoning damage. A trampled opponent can attempt either an attack of opportunity at a -4 penalty or a Reflex save (DC 29; for half damage.

Scent (Ex): An indricothere can detect approaching enemies, sniff out hidden foes, and track by sense of smell.

A wild indricothere simply desires to stay alive in a fight. This doesn't mean that indricotheres act in a purely defensive manner, however. If fleeing is not an option, an indricothere lashes out with its head and tries to knock opponents away. Its long neck enables the creature to pack quite a punch with its head butt. The indricothere also uses its feet as potent weapons by stamping and trampling foes into jelly.

Giants that use indricotheres as mounts employ an effective variant tactic - forcing the mount within reach of a foe, whereupon the indricothere uses its head butt and possibly follows up with a knock back attempt. If the knock back is successful, both the giant and the indricothere take advantage of the attacks of opportunity generated as the foe leaves both creatures' threatened areas.