Legendary Resistance (1/Day). If the baby tarrasque fails a saving throw, it can choose to succeed instead.

Magic Resistance. The baby tarrasque has advantage on saving throws against spells and other magical effects.

Siege Monster. The baby tarrasque deals double damage to objects and structures.

Stone Throw.  Ranged Attack: +2 to hit, range 200 ft., one target. Hit: 18 (4d6 +10). On a hit, The target must make a DC 15 strength saving throw or be knocked prone.

Multiattack. The baby tarrasque can use its Frightful Presence. It then makes two, attacks: one with its bite, one with its claws, It can use its Swallow instead of its bite.

Bite. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 31 (4d12 + 5) piercing damage. If the target is a creature, it is grappled (escape DC 20). Until this grapple ends, the target is restrained, and the baby tarrasque can't bite another target.

Claw. Melee Weapon Attack: +5 to hit, reach 15ft., one target. Hit: 21 (4d8 + 5) slashing damage.

Frightful Presence. Each creature of the baby tarrasque's choice within 120 feet of it and aware of it must succeed on a DC 13 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, with disadvantage if the tarrasque is within line of sight, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the baby tarrasque's Frightful Presence for the next 24 hours.

Swallow. The baby tarrasque makes one bite attack against a Large or smaller creature it is grappling. If the attack hits, the target takes the bite's damage, the target is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the baby tarrasque, and it takes 28 (8d6) acid damage at the start of each of the baby tarrasque's turns.

If the baby tarrasque takes 20 damage or more on a single turn from a creature inside it, the baby tarrasque must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 5 feet of the baby tarrasque. If the baby tarrasque dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 15 feet of movement, exiting prone.

Burrow: The baby tarrasque is a proficient burrower and can use it to escape from it's attackers.

The tarrasque 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 tarrasque regains spent legendary actions at the start of its turn.

Attack. The tarrasque makes one claw attack or tail attack.

Move. The tarrasque moves up to half its speed.

Chomp (Costs 2 Actions). The tarrasque makes one bite attack or uses its Swallow.