n gargantuan animal dinosaur 

Perception +16; low-light vision, scent (imprecise) 30 feet

Skills Athletics +23

Str +9 Dex +0 Con +5 Int -4 Wis +2 Cha +1

AC  28; Fort +21, Ref +14, Will +16

HP 220

Speed 35 feet

Melee [>] tail +23 (sweep, reach 20 feet), Damage 2d10+13 bludgeoning plus Improved Knockdown

Melee [>] foot +23 (reach 15 feet), Damage 2d8+13 bludgeoning

Tail 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

Bestiary, page 100.