Elemental Armor

A protective magical force appears around you, manifesting as a raging elemental suit of armor. You count as a size larger and gain 70 (8d10+15) temporary hit points that disappear when you lose concentration or the spell ends. The type of gem the spell consumes determines the spell's outcome: Ruby for fire, diamond for air, sapphire for water, and topaz for earth.

1. Fire. A crackling inferno engulfs your body. Any enemy in within 10 feet of you when you cast this spell must succeed on a Dexterity saving throw with a DC equal to your spell save DC. On a failed save, the creature takes 4d6 fire damage or half as much on a successful one. Any attack you make deals an additional 2d6 fire damage.

2. Air. You control a whipping tornado that sucks in everything near you. Any enemy creature within 10 feet must make a Strength saving throw with a DC equal to your spell save DC. Every creature that fails the save is pushed 10 feet directly away from you, falls prone, and suffers 2d6 bludgeoning damage. On a successful save, a creature takes half as much damage and stands its ground. You also gain a flying speed equal to your walking speed.

3. Water. Four long tendrils extend from the torrent of water that swirls around you. Choose up to four creatures within 15 feet to make a Strength saving throw with a DC equal to your spell save DC. Any creature that fails its save is grappled by the tendril, and takes 2d6 cold damage. When a grappled creature starts its turn it takes 2d6 cold damage and can use an action to attempt the same saving throw to break free. As a bonus action, any free tendril can either attempt another grapple, or make a melee attack (+ your spell attack bonus) against, another creature within 15 feet of you.

4. Earth. The dense rock that encases your body grants an additional +3 AC. As an action you can hurl a boulder at any creature with a 30 foot range using a ranged attack + your spellcasting modifier. The boulder deals 2d6 bludgeoning damage and pushes the target back 10 feet.