Turtle Shell

You touch a creature who isn't wearing armor, and a turtle shell forms of their back until the spell ends. The target's AC becomes 13 and their movement speed is halved. The spells end if you dismiss it as a bonus action. If the creature is not willing, they may make a Strength saving throw against your spell save DC, on a success the spell fails, the creature may reroll this check on their turn as a bonus action.