Water Bubble

Create a bubble that protects you and nearby creatures from outside attacks. The bubble has health equal to 2d6 plus your spell casting modifier. Attacks made on it do not need to roll to hit. If a ranged attack's damage exceeds the bubble's health an attack roll is made, upon success the remaining damage is dealt to the chosen target. If an enemy attempts to walk into the bubble they must preform a dexterity or strength saving throw (AC 8 plus your spell casting modifier) If they fail they're pushed 5 feet back.

Using a Higher-Level Spell Slot.  The bubble gains 1d6 health for each spell slot level above 1