You are naturally adapted to survive extreme heat and arid conditions. You have resistance to fire damage. In addition, you cannot gain exhaustion due to extreme heat, and you require only one gallon of water per week to survive. 

Your body can absorb sunlight for sustenance and healing. If you spend at least 4 hours in direct sunlight, you do not need to eat that day. In addition, when you spend one of more hit dice during a short rest while in direct sunlight, you regain additional hit points equal to your proficiency bonus plus your constitution modifier. 

Your body is covered in sharp spines that grow naturally from your skin. You can retract of expose these spines as a bonus action. While the spines are out, whenever you grapple a creature or become grappled by a creature, it takes piercing damage equal to your proficiency bonus plus your constitution modifier. 

When you  make an unarmed strike, you can deal piercing damage equal to 1d6+your strength modifier instead of the normal damage. 

Once per short rest, as an action, you can unleash a burst of spines in a 10-foot radius around you. Each creature in the area must make a Dexterity saving throw (DC=8+ your CON modifier+ your proficiency bonus) or take 2d8 piercing damage. On a successful save, the creature takes half damage. This damage increases by 1d8 when you reach character levels 5 (3d8), 11 (4d8), and 17 (5d8).