The Suns Shell

You touch a willing creature and create an armor like shell of fire around the target. The target's base AC becomes 13 + its Dexterity modifier. The spell ends when 1 hour has passed or if you dismiss the spell as an action. When the user is grappling an entity and have the spell active, the grappled entity will take 1d4 fire damage for each round that they are grappled whilst the spell is active. Every 3 levels add 1d4 fire damage to the grapple damage.