n huge animal dinosaur 

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

Skills Athletics +21

Str +7 Dex +0 Con +4 Int -4 Wis +2 Cha -1

AC  26; Fort +18, Ref +12, Will +14

HP 140

Frill Defense [R] Trigger The rider is targeted with an attack. Effect Requirements A creature must be mounted on the triceratops. The triceratops intercepts the attack with its bony frill. The rider gains a +2 circumstance bonus to its AC against the triggering attack.

Speed 30 feet

Melee [>] horns +19 (reach 15 feet), Damage 2d8+9 piercing plus Knockdown

Melee [>] foot +19 (reach 10 feet), Damage 2d6+9 bludgeoning

Lumbering Charge [>] The triceratops Strides up to 10 feet and then makes a Strike.

Trample [>>>] Large or smaller, foot, DC 26

Vicious Gore A triceratops deals 2d6 extra persistent bleed damage to prone targets it hits with its horns.

Bestiary, page 99.