You cause yourself to gain a body made of pure elemental material.

Combat Avatar. The target's size triples in all dimensions, and its weight is multiplied by 12. This growth increases its size by two categories-- from Medium to Huge, for example. If there isn't enough room for the target to double its size, the creature or object attains the maximum possible size in the space available. Until the spell ends, the target also has advantage on Strength checks and Strength saving throws. The target's weapons also grow to match its new size. While these weapons are enlarged, the target's attacks with them deal 3d6 (bludgeoning, fire, cold, lightning). While in fire, water or lightning form the caster can move through space 1 inch in diameter or larger. While in lightning, fire, or ice form all enemies within 10 feet of caster take 2d4 (fire, cold, lightning) damage on each of the casters turns. While in wood form the caster can use an action to call up an Awakened Tree, this recharges after 1d4 hours. While in water form the caster can call up an Water Elemental, this recharges after 1d4 hours.