Susanoo

You create a huge humanoid skeleton made of energy around yourself granting you protection from everything. You gain immunity to everything. While concentrating you take a cumulative 1d6 unpreventable damage at the start of your turn. This damage causes you to make a concentration check, the spell does not end on a failure but is suspended until you take a bonus action to remake the skeleton. If you take damage in the meantime, you must still make a concentration check and if you fail, the spell completely ends. The damage caused by the spell can’t be regained by any method other a long rest. This enhanced form makes your weapons have increased damage. It gives 5 extra weapon damage dice. (Eg. A longsword would be 6d8). After 2 rounds the form becomes a muscular humanoid but with no skin, this causes the weapon to deal an extra 3d6 fire damage. After another 2 rounds it is now a fully formed huge humanoid made of energy. Your weapons now hit critically on 18-20. You can now cleave with your weapon. When you do, any large or smaller creature within a 15 ft. Cone must make a Dexterity saving throw or take your full weapon damage. Half on a successful saving throw.