Cilli's Exploding Bubble

As an action, you choose one friendly creature, or yourself, within 20 feet of you; creating a sparkling bubble of Abjuration magic. The Bubble has 100 HP, and causes all incoming damage to be cut in half. The bubble lasts for One Minute or if all 100 HP is dealt to the Bubble. When the Bubble pops, all creatures within 5 feet of the target must make a DEX saving throw, or take 10d10 Force damage on a failed save, or half as much on a passed save.