Bubble Shield

As a bonus action, you can create a bubble-like shield around a creature of your choosing. This shield has hit points equal to the casters level, when broken any creature within 10ft of the shield must make a Dexterity saving throw or take 3d4 piercing damage on a failed save, or half as much on a successful one. In appearance, the shield is transparent and acts like glass, the shield will also follow the creature it has been attached to around and is only big enough to fit the target creature inside.