Baby Rex (Juvenile T-Rex)

Motion-Perception Vision. The T-Rex treats all creatures that have not moved or taken an action since the end of the T-Rex’s last turn as invisible. At the start of T-Rex’s turn, any creature may use their reaction to hold still, causing the T-Rex to make bite attacks against it at disadvantage until the start of T-Rex’s next turn. Creatures that use their reaction in this way cannot move on their next turn.

Pounce. If the Tyrannosaurus moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 12 Strength saving throw or be knocked prone. If the target is prone, the tyrannosaurus can make one bite attack against it as a bonus action.

Bite. Melee Weapon Attack : +8 to hit, reach 5 ft., one target. Hit: 20 (4d6 + 6) piercing damage. If the target is a small or tiny, it is grappled (escape DC 12). Until this grapple ends, the target is restrained and the T-Rex can't bite another target.

Claw. Melee Weapon Attack:  +8 to hit, reach 5 ft., one target. Hit: 10 (1d6 + 6) slashing damage.