Arctic Aegis

In response to being attacked, you swiftly summon a barrier of shimmering ice. The icy shield has 20 hit points and absorbs the damage you would have taken, which it deducts from its hit points. This shield has vulnerability to fire and immunity to cold damage. If the shield has points remaining you can transmute it into an icicle and make a ranged spell attack with it as a part of the reaction against the attacking creature. On hit the target takes 1d8 + Remaining HP as Cold damage.

At Higher Levels: When you use this reaction with a spell slot of 4th or higher, the initial hitpoints of the shield increase by five for each slot and the damage die increases by 1d8.