Legendary Resistance (3/Day). If Zorah Magdaros fails a saving throw, it can choose to succeed instead.

Magma Carapace. Zorah Magdaros deal 3d6 fire damage every turn to creatures touching it.

Siege Monster. Zorah Magdaros deals double damage to objects and structures.

Multiattack. Zorah Magdaros can use its Frightful Presence. It then makes four attacks: one with its bite, two with its claws, and one with its head smash. It can use its Swallow instead of its bite.

Bite. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 36 (4d12 + 10) piercing damage. If the target is a creature, it is grappled (escape DC 20). Until this grapple ends, the target is restrained, and Zorah Magdaros can't bite another target.

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

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

Magma Core Explosion. Zorah Magdaros attacks creatures on its back. Each creature in a 20 foot diameter at a point of its back Zorah Magdaros' choice must make a DC 25 Dexterity saving throw. A creature takes 40 (6d10 + 10) fire damage on a failed save, or half as much on a successful one. Creatures that fail the save by 5 or more are pushed back 5 feet and knocked prone.

Spew Debris (Recharge 5–6). Zorah Magdaros exhales magma in a 90-foot cube. Each creature in that area must make a DC 25 Dexterity saving throw. A creature takes 33 (13d10) fire damage on a failed save, or half as much damage on a successful one.

Frightful Presence. Each creature of Zorah Magdaros' 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 Zorah Magdaros 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 Zorah Magdaros' Frightful Presence for the next 24 hours.

Swallow. Zorah Magdaros 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 Zorah Magdaros, and it takes 56 (16d6) acid damage at the start of each of Zorah Magdaros' turns.

If Zorah Magdaros takes 60 damage or more on a single turn from a creature inside it, Zorah Magdaros 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 Zorah Magdaros. If Zorah Magdaros dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Zorah Magdaros 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. Zorah Magdaros regains spent legendary actions at the start of its turn.

Attack. Zorah Magdaros makes one claw attack

Move. Zorah Magdaros moves up to half its speed.

Chomp (Costs 2 Actions). Zorah Magdaros makes one bite attack or uses its Swallow.