BrontosaurusCreature 10
Source Pathfinder Monster Core
Perception +16 (low light vision, scent (imprecise) 30 feet)
Languages none
Skills Athletics +23
Str +9, Dex +0, Con +5, Int -4, Wis +2, Cha +1
AC 28; Fort +21; Reflex +14; Will +16;
HP 220
Speed 35 feet
Tail
+23 (+18, +13) to hit (reach 20, sweep) 2d10+13 BludgeoningFoot
+23 (+18, +13) to hit (reach 15, unarmed) 2d8+13 BludgeoningTail Sweep

The brontosaurus makes a tail Strike and compares the attack roll to the AC of up to three foes, each of whom must be within its tail's melee reach and adjacent to at least one other target. It rolls damage only once and applies it to each creature hit.
A Tail Sweep counts as two attacks for its multiple attack penalty.
Trample
Huge or smaller, foot, DC 29 reflex
The monster Strides up to double its Speed and can move through the spaces of creatures of the listed size, Trampling each creature whose space it enters. The monster can attempt to Trample the same creature only once in a single use of Trample. The monster deals the damage of the listed Strike, but trampled creatures can attempt a basic Reflex save at the listed DC (no damage on a critical success, half damage on a success, double damage on a critical failure).
Improved Knockdown
Trigger The monster's last action was a successful Strike that lists Improved Knockdown in its damage entry
Effect The monster attempts to [/act trip] the creature as a free action. This attempt neither applies nor counts toward the monster's multiple attack penalty.
Brontosauruses are truly gigantic behemoths, herbivores large enough to be unafraid of all but the most massive predators. Brontosauruses have stout bodies and long, sinuous necks and tails. Although their feet are capable of crushing entire buildings, these herbivores are generally considerate of where they step.
Remnants from the world's primeval era, these enormous reptilian animals still exist in large numbers in remote wildernesses or underground in magical Darklands caverns. Lizardfolk, orcs, giants, and other humanoids who live near dinosaurs use the animals as mounts, guards, or hunting beasts. Occasionally, rich nobles will collect dinosaurs to display them in menageries, which almost inevitably leads to cast-offs being nursed back to health by druids and other champions of nature. When dinosaurs establish themselves in regions outside their normal habitats, it's often the result of a large collection being released.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
AnimalAn animal is a creature with a relatively low intelligence. It typically doesn't have an Intelligence attribute modifier over –4, can't speak languages, and can't be trained in Intelligence-based skills.
DinosaurThese reptiles have survived from prehistoric times.