n large animal dinosaur 

Perception +10; low-light vision

Skills Athletics +13

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

AC  21; Fort +12, Ref +8, Will +8

HP 70

Speed 25 feet

Melee [>] tail +13 (backswing, reach 10 feet), Damage 2d6+5 bludgeoning plus Punishing Tail

Melee [>] foot +13, Damage 1d8+5 bludgeoning

Punishing Tail A creature hit by the pinacosaurus's tail must attempt a DC 21 Fortitude save. On a failure, it's slowed 1 until the end of its next turn; on a critical failure, it's stunned until the end of its next turn.

Trample [>>>] Small or smaller, foot, DC 21

Extinction Curse #1: The Show Must Go On, page 50.