Multiattack. The Tyrannosaurus makes two attacks: one bite and one tail. It can't make both attacks against the same target
Bite. Melee weapon attack: +10 to hit, reach 10 ft, one target. hit: 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 tyrannosaurus can't bite another target.
Tail. Melee Weapon Attack: +10 to hit, reach 10ft., one target. Hit: 3d8+7 bludgeoning damage.
the Tyrannosaurus can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The tyrannosaurus regains spent legendary actions at the start of its turn.
Entangle (2 actions): Grasping vines and roots sprout in a 10 foot radius around the tyrannosaurus. These wither after 1 minute. For the duration, that area is difficult terrain for non plant creatures. In addition any creature of the Tyrannosaurus' choice in that area when the plants appear must succeed on a DC 14 strength check or be restrained. A creature can use it's action to try to free itself or another restrained creature with the same strength check.
Tail attack.
the tyrannosaurus moves up to half its speed.
Blight Walk: the wolf can move through and breath in blighted ground as if it were air. It has advantage on stealth checks when moving under the blight.
Pack Tactics: the wolf has advantage on an attack roll against a creature if at least one of its allies is within 5 feet of the creature and the ally isn't incapacitated.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit 2d6+3 piercing damage. the target must succeed on a DC 11 Strength saving throw or be knocked prone.
Bind. Grapple Attack: reach 10 ft., one target. Target must make a DC 12 Strength saving throw or be restrained. A creature can use it's action to free itself or another restrained creature by making the same saving throw.