Legendary Resistance (1/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.

Multiattack. The tarrasque makes five attacks: one with its bite, two with its claws, one with its horns, and one with its tail. It can use its Swallow instead of its bite.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 17 (2d12 + 5) piercing damage. If the target is a creature, it is grappled (escape DC 15). Until this grapple ends, the target is restrained, and the tarrasque can’t bite another target.

Claw. Melee Weapon Attack: +10 to hit, reach 10ft., one target. Hit: 13 (2d8 + 5) slashing damage.

Horns. Melee Weapon Attack: +10 to hit, reach 5ft., one target. Hit: 15 (2d10 + 5) piercing damage.

Tail. Melee Weapon Attack: +10 to hit, reach 10ft., one target. Hit: 11 (2d6 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.

Swallow. The 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 tarrasque, and it takes 28 (9d6) acid damage at the start of each of the tarrasque’s turns.

If the tarrasque takes 30 damage or more on a single turn from a creature inside it, the tarrasque must succeed on a DC 22 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the tarrasque. If the tarrasque dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

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.