Actions

Multiattack. Tarrasque can use its Frightful Presence. It then makes five attacks: one with its bite, two with its claws or Terra Cleaver, one with its horns, and one with its tail. It can use its Swallow instead of its bite if in its true form.

Bite. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 29 (3d12 + 10) piercing damage in humanoid form, or 36 (4d12 + 10) piercing damage in true form. If the target is a creature and Tarrasque is in its true form, the target is grappled (escape DC 20). Until this grapple ends, the target is restrained, and Tarrasque can't bite another target.

Claw (True Form Only). Melee Weapon Attack: +19 to hit, reach 15ft., one target, see colossal. Hit: 28 (4d8 + 10) slashing damage.

Terra Cleaver (Humanoid Form Only). Melee Weapon Attack: +22 to hit, reach 10ft., one target. Hit: 23 (3d6 +13) slashing damage plus 9 (2d8) force damage.

Horns. Melee Weapon Attack: +19 to hit, reach 10ft., one target, see colossal. Hit: 26 (3d10 + 10) piercing damage in humanoid form, or 32 (4d10 + 10) piercing damage in true form.

Tail. Melee Weapon Attack: +19 to hit, reach 20ft., one target, see colossal. Hit: 20 (3d6 + 10) bludgeoning damage in humanoid form, or 24 (4d6 + 10) bludgeoning damage in true form. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be knocked prone.

Frightful Presence. Each creature of the tarrasque's choice within 120 feet of it and aware of it must succeed on a DC 17 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 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 Tarrasque's Frightful Presence for the next 24 hours.

Swallow (True Form Only). 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 of Tarrasque, and it takes 56 (16d6) acid damage at the start of each of Tarrasque's turns.

If Tarrasque takes 60 damage or more on a single turn from a creature inside it, Tarrasque must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Tarrasque. If Tarrasque dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Primal Roar (True Form Only, Recharge 6). Tarrasque releases an earth-shattering bellow. All creatures within a 120ft cone must make a DC 27 Constitution saving throw, taking 91 (26d6) thunder damage, or half on a successful save. Additionally, all creatures within a 120ft radius of Tarrasque must make a DC 27 saving throw or take 35 (10d6) thunder damage, or half on a successful save.