Blazing Skin. Zorah Magdaros is covered in trails of flowing Lava. Any creature that starts their turn within 15 feet of Zorah Magdaros or makes a Melee Attack against Zorah Magdaros takes 30 (10d6) Fire Damage. 

Migratory Mountain. Zorah Magdaros is the size of a mountain, though it migrates across the world. No one knows where it's headed, only that if you get in its way, you'll be crushed or simply burn away. 

Earth Shattering Size. Zorah Magdaros is so immense in size, that every time it moves a creature within 500 feet of it must make a Dexterity Saving Throw (DC 26) or lose their footing and fall Prone. 

Bite. Melee Weapon Attack: +28 to hit, reach 20ft., one target, Hit: 34 (4d12+10) Piercing Damage plus 30 (10d6) Fire Damage. 

Claw. Melee Weapon Attack: +28 to hit, reach 15 ft., one target, Hit: 25 (3d10+10) Slashing Damage plus 30 (10d6) Fire Damage. 

Earthquake. Zorah Magdaros stomps once, sending an explosive shockwave through the ground. Each creature within 500 feet must Succeed on a Dexterity Saving Throw (DC 26) or be knocked Prone and take 60 (10d12) Bludgeoning Damage. 

Magma Armour. If Zorah Magdaros would be hit with a Melee Attack, it can use its reaction to raise its AC by 10 and deal 30 (10d6) Fire Damage to the attacking creature. 

Zorah Magdaros has 3 Legendary Actions it can use to make one of the following actions. Only one option can be used at a time, and only at the end of another creature's turn. 

Bite. Zorah Magdaros makes a Bite attack. 

Claw. Zorah Magdaros makes a Claw attack. 

Earthquake (Costs 2 Actions). Zorah Magdaros makes an Earthquake attack. 

On Initiative count 15, Zorah Magdaros can choose to make one of the following actions. 

Volcanic Temper. Zorah Magdaros causes the Volcanic hump on its back to erupt, every creature within 500 feet must make a Dexterity Saving Throw (DC 26), taking 90 (30d6) Fire Damage on a fail and half as much on a success. 

Shattering Stomp. Zorah Magdaros makes an Earthquake attack, however, in addition to the attack a 500 ft. long, 50 ft. wide and 250 ft. deep chasm opens. Any creature near the chasm, if they failed the Saving Throw, they fall into the chasm taking 25d6 Bludgeoning Damage and being trapped.