Adult Trirannosaurus

Keen Hearing and Smell. The trirannosaurus has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Siege Monster. The trirannosaurus deals double damage to objects and structures.

Trampling Charge. If the trirannosaurus moves at least 30 ft. straight toward a creature and then hits it with a gore attack on the same turn, that target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the trirannosaurus can make one stomp attack against it as a bonus action.

Combative Mount. A trained dinosaur is proficient with light, medium, and heavy armor.

Multiattack. The trirannosaurus can make three attacks: One with it's Bite and two with its Claw's.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the trirannosaurus can't bite another target.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) slashing damage.

Tail Whip. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.

Impale. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 24 (4d8 + 6) piercing damage.

Crushing Stomp. Melee Weapon Attack: 11 to hit, reach 5 ft., one prone creature. Hit: 22 (3d10 + 6) bludgeoning damage.

Terrifying Roar (Recharge 5-6). Each time the trirannosaurus roars each creature within 120 feet and able to hear the roar must make a saving throw. Each creature that fails a DC 15 Wisdom saving throw is frightened for 1 minute. A Frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.