Multiattack

The tyrannosaurus makes a bite attack and a tail attack against two different targets.

Bite

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 25 (3d12 + 6) piercing damage. If the target is a creature it is grappled (escape DC 17). Until this grapple ends the tyrannosaurus can't bite a different creature and it has advantage on bite attacks against the grappled creature.

Tail

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage.