Legendary Resistance (6/Day). If the tarrasque fails a saving throw, it can choose to succeed instead.

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

Magic Weapons. The tarrasque's natural weapons are considered magical, overcoming immunities and resistances stating as such.

Reflective Carapace. If the tarrasque is targeted by a Magic Missile spell or a spell that requires a ranged attack roll, roll 1d6. On a 1–5, the tarrasque is unaffected. On a 6, the tarrasque is unaffected and reflects the spell, turning the caster into the target.

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

Regenerative Carapase. At the start of each of the tarrasque's turns, it regains 20 hit points.

Overwhelming Strength. Whenever the tarrasque makes a strength saving throw or check, if the result of the die is less than its strength score, it can use its strength score in place of the roll.

Unbreakable(3/day). Whenever the tarrasque takes damage, it instead doesn't take that damage.

Strength To Solve All. The tarrasque can add its strength modifier to Intimidation checks, Perception checks, and Dexterity saving throws. In addition, when the tarrasque is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.

Multiattack. The tarrasque makes one Bite attack and three other attacks, using Claw, Tail or Horn in any combination.

Bite. Melee Attack Roll: +19, reach 15 ft. Hit: 36 (4d12 + 10) Piercing damage, and the target has the Grappled condition (escape DC 20). Until the grapple ends, the target has the Restrained condition and can’t teleport.

Claw. Melee Attack Roll: +19, reach 15 ft. Hit: 28 (4d8 + 10) Slashing damage.

Horns. Melee Weapon Attack: +19 to hit, reach 10ft., one target. Hit: 32 (4d10 + 10) piercing damage.

Tail. Melee Attack Roll: +19, reach 30 ft. Hit: 23 (3d8 + 10) Bludgeoning damage. If the target is a Huge or smaller creature, it has the Prone condition.

Thunderous Bellow (Recharge 5–6). Constitution Saving Throw: DC 27, each creature and each object that isn’t being worn or carried in a 150-foot Cone. Failure: 78 (12d12) Thunder damage, and the target has the Deafened, Stunned,                                              Frightened conditions until the end of its next turn. Success: Half damage only.

Swallow. Strength Saving Throw: DC 27, one Large or smaller creature Grappled by the tarrasque (it can have up to six creatures swallowed at a time). Failure: The target is swallowed, and the Grappled condition ends. A swallowed creature has the Blinded and Restrained conditions and can’t teleport, it has Total Cover against attacks and other effects outside the tarrasque, and it takes 56 (16d6) Acid damage at the start of each of the tarrasque’s turns.

If the tarrasque takes 60 damage or more on a single turn from a creature inside it, the tarrasque must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, each of which falls in a space within 10 feet of the tarrasque and has the Prone condition. If the tarrasque dies, any swallowed creature no longer has the Restrained condition and can escape from the corpse using 20 feet of movement, exiting Prone.

Stampede. The tarrasque moves half of its speed without provoking opportunity attacks. Each creature that comes within 10 ft of the tarrasque at the start, during, or end of the movement must make a DC 27 dexterity saving throw or take 30(10d6) bludgeoning damage, and have the prone condition if they are large or smaller.

The tarrasque has 5 reactions, and it regains all of its reactions at the start of its turn. If the tarrasque loses its reactions, it instead loses only one reaction. It can take multiple reactions in a turn.

Primeval Dominance(5/Day). If a creature the tarrasque can see uses a legendary action or legendary resistance, it must succeed a DC 27 charisma saving throw or lose that legendary action or resistance without gaining the benefits of doing one.

Indomitable Might (3/Day). At the start of another creature's turn, the tarrasque can choose to instead immediately end that creature's turn before it gets to do anything. Any effects that happen at the start of its turn or at the end of it still apply.

Retaliate. In response to taking damage from an attack or spell, the tarrasque can move up to 30 ft. toward the attacker without provoking opportunity attacks. It can then immediately make a claw attack against the creature.

Legendary Action Uses: 5. Immediately after another creature’s turn, the tarrasque can expend a use to take one of the following actions. The tarrasque regains all expended uses at the start of each of its turns.

Onslaught. The tarrasque moves up to half its Speed, and it makes one Claw or Tail attack.

World-Shaking Movement. The tarrasque moves up to its Speed. At the end of this movement, the tarrasque creates an instantaneous shock wave in a 60-foot Emanation originating from itself. Creatures in that area lose Concentration and, if Medium or smaller, have the Prone condition. The tarrasque can’t take this action again until the start of its next turn.

Tail Sweep. The tarrasque sweeps its tail in a 30-foot cone; it makes a tail attack against each creature in the radius.

Titan assertance(1/Day). The tarrasque takes a turn; this turn doesn't refresh any legendary actions or reactions.