Bone Shield

You generate a barrier of elongated femurs that protects you. You reduce the incoming damage by 1d12, and if the attacking enemy is within 10 feet of you, the osseous barrier explodes, dealing slashing damage to them equal to the amount reduced.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage reduction increases by 1d12 for each slot level above 1st.

From Steinhardt's Guide to the Eldritch Hunt.